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INTER-UNIVERSITY CENTRE FOR ASTRONOMY AND ASTROPHYSICS (An Autonomous Institution of the University Grants Commission) Design, Typesetting and Layout Manjiri Mahabal e-mail : [email protected] Annual R Annual R Annual R Annual R Annual Report eport eport eport eport (April 1, 2005 - March 31, 2006) Editor T. Padmanabhan e-mail : [email protected]

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INTER-UNIVERSITY CENTRE FORASTRONOMY AND ASTROPHYSICS

(An Autonomous Institution of the University Grants Commission)

Design, Typesetting and Layout

Manjiri Mahabale-mail : [email protected]

Annual RAnnual RAnnual RAnnual RAnnual Reporteporteporteporteport(April 1, 2005 - March 31, 2006)

Editor

T. Padmanabhane-mail : [email protected]

Phone (91) (20) 2560 4100

Fax (91) (20) 2560 4699

[email protected]

Universal Resource Locator (URL)http://www.iucaa.ernet.in

Postal AddressPost Bag 4, Ganeshkhind, Pune 411 007, India

LocationMeghnad Saha Road, Pune University Campus, Ganeshkhind, Pune 411 007, India

HIGHLIGHTS OF 2005- 2006HIGHLIGHTS OF 2005- 2006HIGHLIGHTS OF 2005- 2006HIGHLIGHTS OF 2005- 2006HIGHLIGHTS OF 2005- 2006

This annual report covers the activities of IUCAA during its eighteenth year, April 2005-March 2006. The endeavoursof IUCAA span different fronts, as outlined in the pages of this report. Here is a quick summary and highlights.

IUCAA has an academic strength of 15 core faculty members (academic), 15 post-doctoral fellows and 18 researchscholars. The core research programmes by these academics span a variety of areas in astronomy and astrophysics.These topics include quantum theory and gravity, classical gravity, gravitational waves, cosmology and structureformation, cosmic microwave background anisotropy, observational cosmology, magnetic fields in astrophysics, activegalactic nuclei, quasar and intergalactic medium, galaxies high energy astrophysics, stars and interstellar medium andinstrumentation. These research activities are summarised in pages 15-39. The publications of the IUCAA members,numbering to about 75 in the current year are listed in pages 67-70. IUCAA members also take part in pedagogicalactivities, the details of which are given in pages 77-78 of this report.

The extended academic family of IUCAA consists of about 90 Visiting Associates, who have been active in severaldifferent fields of research. Pages 40-57 of this report highlights their research contributions spanning gravitationaltheory and gravitational waves, classical and quantum cosmology, galaxies and quasars, compact objects and X-raybinaries, stars, stellar systems and interstellar medium, Sun and solar system, plasma physics, dynamics, theoreticalphysics, e-content development, instrumentation and radio astrophysics. The resulting publications, numbering toabout 95 are listed in pages 71-76 of this report. A total of about 1216 person-days were spent by Visiting Associatesat IUCAA during this year. In addition, IUCAA was acting as host to about 400 visitors through the year.

IUCAA conducts its graduate school jointly with the National Centre for Radio Astrophysics, Pune. Among theresearch scholars, three students have successfully defended their theses and obtained Ph.D. degrees from theUniversity of Pune during the year. Summary of their theses appears in pages 58-66.

Apart from these activities, IUCAA conducts several workshops, schools, and conferences each year, both at IUCAAand at different university/college campuses. During this year, there were 7 such events in IUCAA and 6 were heldat other universities/colleges under IUCAA sponsorship.

Another main component of IUCAA’s activities is its programme for Science Popularisation. On the National ScienceDay, several special events were organised. There were posters displayed by the academic members of IUCAA, whichelaborated on the research work at IUCAA and topics in the field of astronomy. There were public lectures given bythe faculty members and programmes for school students consisting of quiz, essay and drawing competitions. Duringthe Open Day, more than 3000 people visited IUCAA.

These activities were ably supported by the scientific and technical, and administrative staff (20 and 33 in numberrespectively) who should get the lion’s share of the credit for successful running of the programmes of the centre. Thescientific staff also looks after the major facilities like library, computer centre, and instrumentation lab. A brief updateon these facilities is given on pages 101-106 of this report.

A major milestone which we reached during the year is the successful completion of IUCAA Girawali Observatory andthe installation of the Telescope. The final acceptance was done in early February and the Telescope was handed over to IUCAAon February 14, 2006. IUCAA scientists are actively involved in the task of making the Telescope ready for observationsas soon as possible.

T. Padmanabhan Editor

CONTENTS

The Council and the Governing Board ...........................................................................................................................1The CouncilThe Governing Board

Honorary Fellows and Visiting Professors .................................................................................................................................2

Statutory Committees ....................................................................................................................................................2The Scientific Advisory CommitteeThe Users' CommitteeThe Academic Programmes CommitteeThe Standing Committee for AdministrationThe Finance Committee

Members of IUCAA ......................................................................................................................................................4

Visiting Members of IUCAA .........................................................................................................................................6

Organizational Structure of IUCAA's Academic Programmes ................................................................................ 11

The Director's Report .................................................................................................................................................. 12

Congratulations to ....................................................................................................................................................... 13

Calendar of Events ........................................................................................................................................................ 14

Academic Programmes ................................................................................................................................................ 15

(I) Research by Resident Members .......................................................................................................................... 15Quantum Theory and GravityClassical GravityGravitational WavesCosmology and Structure FormationCosmic Microwave Background AnisotropyObservational CosmologyMagnetic Fields in AstrophysicsActive Galactic Nuclei, Quasar and Intergalactic MediumGalaxiesHigh Energy AstrophysicsStars and Interstellar MediumInstrumentation

(II) Research by Visiting Associates ......................................................................................................................... 40

(III) IUCAA-NCRA Graduate School....................................................................................................................................... 58

(IV) Publications ........................................................................................................................................................ 67

(V) Pedagogical Activities ........................................................................................................................................ 77

(VI) Colloquia, Seminars, etc. .................................................................................................................................... 79

(VII) Talks at IUCAA Workshops or at Other Institutions ......................................................................................... 81

(VIII) Scientific Meetings and Other Events ................................................................................................................ 87

Public Outreach Programmes ..................................................................................................................................... 95

Facilities ..................................................................................................................................................................... 101(I) Computer Centre(II) Library and Publications(III) Instrumentation Laboratory(IV) IUCAA Girawali Observatory(V) Virtual Observatory - India(VI) IUCAA Radio-Physics Training and Educational Facility

IUCAA Reference Centres (IRCs) ........................................................................................................................... 107

Seventeenth IUCAA Foundation Day Lecture ......................................................................................................... 111

1

The Counciland the Governing Board

The Council(As on 31st March, 2006)

President

Sukhadeo Thorat,Chairperson,University Grants Commission, New Delhi.

Vice-President

V.N. Rajasekharan Pillai,Vice-Chairperson,University Grants Commission, New Delhi.

Members

N. Mukunda,(Chairperson, Governing Board),Indian Academy of Sciences, Bangalore.

Mustansir Barma,Department of Theoretical Physics,Tata Institute of Fundamental Research, Mumbai.

A. N. Basu,Vice-Chancellor,Jadavpur University, Calcutta.

S. K. Dube,Director,Indian Institute of Technology, Kharagpur.

Ratnakar Gaikwad,Acting Vice-Chancellor,University of Pune.

Rajen Harshe,Vice-Chancellor,University of Allahabad.

Seyed E. Hasnain,Vice-Chancellor,University of Hyderabad.

A.K. Kembhavi,IUCAA, Pune.

Vijay Khole,Vice-Chancellor,University of Mumbai.

Arvind Kumar,Centre Director,

Homi Bhabha Centre for Science Education, Mumbai.

R.A. Mashelkar,Director General,Council of Scientific and Industrial Research,New Delhi.

S. Mukherjee,Department of Physics,North-Bengal University,Darjeeling, West Bengal.

K. Ramamurthy Naidu,506, Dwarakamai Apartment,Navodaya Colony, Hyderabad.

G. Madhavan Nair,Chairman,Indian Space Research Organization, Bangalore.

Rajaram Nityananda,Centre Director,National Centre for Radio Astrophysics, Pune.

Deepak Pental,Vice-Chancellor,University of Delhi, Delhi.

G. Rajasekaran,The Institute of Mathematical Sciences, Chennai.

V. S. Ramamurthy,Secretary to the Government of India,Department of Science and Technology, New Delhi.

Amitava RaychaudhuriDirectorHarish-Chandra Research Institute, Allahabad.

K.L. Sharma,Vice-ChancellorUniversity of Rajasthan, Jaipur.

Mool Chand Sharma,Secretary,University Grants Commission, New Delhi.

C.V. Vishveshwara,Honorary Director,Jawaharlal Nehru Planetarium, Bangalore.

The following members have served in the Council forpart of the year

A.S. Nigavekar,Chairperson,University Grants Commission, New Delhi.

2

Ashok Kumar Gupta,J.K. Institute of Applied Physics,University of Allahabad.

Kota Harinarayana,Vice-Chancellor,University of Hyderabad.

A.S. Kolaskar,Vice-Chancellor,University of Pune.

Deepak Nayyar,Vice-Chancellor,University of Delhi.

Ved Prakash,Secretary,University Grants Commission, New Delhi.

H.R. Singh,Vice-Chancellor,University of Allahabad.

Member SecretaryN.K. Dadhich,Director, IUCAA.

The Governing Board As on 31st March, 2006)

Chairperson

N. Mukunda.

Members

S. K. DubeRatnakar GaikwadRajen HarsheSeyed E. HasnainA.K. KembhaviK. Ramamurthy NaiduRajaram NityanandaG. RajasekaranMool Chand SharmaC.V. Vishveshwara

The following members have served in the GoverningBoard for part of the year

Ashok Kumar GuptaKota HarinarayanaA.S. KolaskarVed PrakashH.R. Singh

Member SecretaryN.K. Dadhich

Honorary Fellows

Geoffrey Burbidge,University of California,Centre for Astronomy and Space Sciences, U.S.A.

E. Margaret Burbidge,University of California,Centre for Astronomy and Space Sciences, U.S.A.

Jurgen EhlersMax-Planck Institute for Gravitational Physics,Golm, Germany.

A. Hewish,University of Cambridge, U.K.

Gerard 't Hooft,Spinoza Institute, The Netherlands.

Donald Lynden-Bell,Institute of Astronomy,University of Cambridge, U.K.

Yash Pal, Noida.

Allan Sandage,The Observatories of Carnegie Institute of Washington,U.S.A.

P.C. Vaidya,Gujarat University, Ahmedabad.

Visiting Professors

Russell Cannon,Anglo-Australian Observatory, Australia.

Anvar Shukurov,University of Newcastle, UK.

Alexei Starobinsky,Landau Institute for Theoretical Physics, Russia.

Statutory Committees

The Scientific Advisory Committee (SAC)

Abhay Ashtekar,Center for Gravitation, Physics and Geometry,The Pennsylvania State University, U.S.A.

3

Rohini Godbole,Centre for Theoretical Studies,Indian Institute of Science, Bangalore.

John Hearnshaw,University of Canterbury,Christchurch, New Zealand.

Umesh C. Joshi,Physical Research Laboratory, Ahmedabad.

Alain Omont,Institut D’Astrophysique de Paris, France.

S.K. Pandey,School of Studies in Physics,Pandit Ravishankar Shukla University, Raipur.

T.P. Prabhu,Indian Institute of Astrophysics, Bangalore.

Ashoke Sen,Harish-Chandra Research Institute, Allahabad.

N.K. Dadhich, (Convener)IUCAA, Pune.

The Users’ Committee

N.K. Dadhich, (Chairperson)DirectorIUCAA, Pune.

A.K. Kembhavi, (Convener)IUCAA, Pune.

Narayan Banerjee,Department of Physics,Jadavpur University, Kolkata.

Lakshman Chaturvedi,Vice-Chancellor,Pandit Ravishankar Shukla University, Raipur.

Mushirul Hasan,Vice-Chancellor,Jamia Millia Islamia, New Delhi.

P.K. Abdul Azis,Vice-Chancellor,Cochin University of Science and Technology, Kochi.

T. Padmanabhan,IUCAA, Pune.

T.R. Seshadri,Department of Physics and Astrophysics,University of Delhi.

The Academic Programmes Committee

N.K. Dadhich (Chairperson)T. Padmanabhan (Convener)J. BagchiS.V. DhurandharRanjan GuptaA. K. KembhaviRanjeev MisraA.N. RamaprakashSwara Ravindranath (from 06.02.2006)Varun SahniTarun SouradeepR. SrianandK. SubramanianS. N. Tandon

The Standing Committee for Administration

N.K. Dadhich (Chairperson)A.K. KembhaviT. PadmanabhanK.C. Nair (Member Secretary)

The Finance Committee

N. Mukunda (Chairperson)P. Agarwal (till 25.09.2005)N.K. DadhichA.K. KembhaviR. NityanandaA. PimpaleV. Prakash (till 30.11.2005)M. Sharma (from 1.12. 2005)S.K. Singh (from 19.12. 2005)K.C. Nair (Non-Member Secretary)

4

Members of IUCAA

Academic

N.K. Dadhich (Director)T. Padmanabhan (Dean, Core Academic Programmes)A.K. Kembhavi (Dean, Visitor Academic Programmes)J. BagchiS.V. DhurandharR. GuptaR. MisraA.N. RamaprakashS. Ravindranath (from 06.02.2006)V. SahniTarun SouradeepR. SrianandK. SubramanianS. N. Tandon

Emeritus Professor

J.V. Narlikar

Scientific and Technical

N.U. BawdekarS.S. BhujbalM.P. BurseS.B. ChavanV. ChellathuraiK.S. ChillalP.A. ChordiaH.K. DasS. Dhurde (from 25.07.2005)S. EngineerG.B. GaikwadS.U. IngaleA.A. KohokV.B. MestryN. Nageswaran (from 04.05.2005)A. ParanjpyeS. PonrathnamV.K. RaiH.K. SahuY. R. Thakare

Administrative and Support

K. C. Nair (Senior Administrative Officer)N.V. AbhyankarV.P. BarveS.K. DalviS.L. GaikwadB.R. GorkhaB S. GoswamiS.B. GujarR.S. Jadhav

B.B. JagadeS.M. JogalekarS.N. KhadilkarS.B. KuriakoseN.S. MagdumM.A. MahabalS. G. MirkuteE.M. ModakK.B. MunuswamyR.D. PardeshiR.V. ParmarB.R. RaoM.S. SahasrabudheV.A. SamakS.S. SamuelB.V. SawantS. ShankarD.R. ShindeV. R. SurveD.M. SusainathanA.A. SyedS.R. TarpheS.K. WagholeK.P. Wavhal

Post-Doctoral Fellows

V. K. AgrawalS. Barway (from 13.03.2006)S. Basak (from 16.08.2005)S. Joshi (from 04.07.2005)M. Joy (from 13.03.2006)A. Mahmood (till 09.12.2005)M. Puravankara (till 08.07.2005)Subharthi RaySuryadeep RayS. Roychoudhury (from 12.01.2006)S. Sen (till 27.04.2005)C.S. Stalin (till 31.05.2005)P. Subramanian

Project (Post-Doctoral Fellows)

P. Hasan (Indo-French Project)R. Sinha (Virtual Observatory Project)(from 24.01.2006)

Research Scholars

A.L. AhujaU. Alam (till 14.11.2005)S. ChakravortyH. ChandJosily Cyraic (till 06.05.2005)A. DeepA. H. Forushani (till 03.02.2006)D. Kothawala (from 22.08.2005)

5

G. MahajanS. MitraH. MukhopadhyayT. NaskarA. RawatS. SamuiS. SarkarA. ShafielooM.K. SrivastavaS. Sur

Temporary/Project/Contractual Appointments

A.P. Chordia (System Engineer) (till 10.02.2006)M.B. Ghule (Steno-Typist, CEC Project) (till 06.03.2006)J.A. Gupchup (Project Officer, Virtual Observatory) (till 21.07.2005)M. S. Kharade (Project Officer , ERNET Project)S. Koshti (Project Scientist, DST - WOSA Scientist)V. Kulkarni (Scientific/Technical Assistant-I, Public Outreach Programme) (till 15.06.2005)P.L. Shekade (System Engineer)P. S. BaratheV. Jagtap (till 21.03.2005)A.P. Kadam (from 14.11.2005)V. Mhaiskar (from 01.09.2005)D. Nandrekar (from 13.03.2006)S.M. Prabhudesai (from 25.07.2005)A. Rupner (from 01.09.2005)S.C. ShahM. Shaikh (from 02.03.2006)

Part Time Consultants

S. S. Bodas (Medical Services) (till 31.08.2005)V. S. Savaskar (Medical Services) (from 01.09.2005)

Long Term Visitors

Arvind GuptaVijay Mohan

6

Visiting Associates of IUCAA

G. Ambika,Department of Physics,Maharaja’s College, Kochi.

D. Badruddin,Department of Physics,Aligarh Muslim University.

Bindu A. Bambah,School of Physics,University of Hyderabad.

A. Banerjee,Department of Physics,Jadavpur University, Kolkata.

N. Banerjee,Department of Physics,Jadavpur University, Kolkata.

S.K. Banerjee,Amity School of Engineering, Noida.

S. Bhowmick,Department of Physics,Barasat Government College, Kolkata.

Pavan Chakraborty,Department of Physics,Assam University, Silchar.

Subenoy Chakraborty,Department of Mathematics,Jadavpur University, Kolkata.

Deepak Chandra,Department of Physics,S.G.T.B. Khalsa College, Delhi.

Suresh Chandra,School of Physical Sciences,Swami Ramanand Teerth Marathwada University,Nanded.

Tanuka Chattopadhyay,Department of Mathematics,Shibpur D.B. College, Howrah.

Sarbeswar Chaudhuri,Department of Physics,Gushkara Mahavidyalaya, Burdwan.

Arnab Rai Choudhuri,Department of Physics,Indian Institute of Science, Bangalore.

M.K. Das,Institute of Informatics and Communication,University of Delhi.

Jishnu Dey,Department of Physics,Presidency College, Kolkata.

Mira Dey,Department of Physics,Presidency College, Kolkata.

Umesh Dodia,Department of Physics,Bhavnagar University.

Ranabir Dutt,Department of Physics,Visva Bharati University, Santiniketan.

D.V. Gadre,ECE Division,Netaji Subhas Institute of Technology, New Delhi.

A.D. Gangal,Department of Physics,University of Pune.

Sushant Ghosh,Department of Mathematics,BITS, Pilani.

Ashok Goyal,Department of Physics,Hansraj College, Delhi.

Abhinav Gupta,Department of Physics,St. Stephen’s College, Delhi.

K.P. Harikrishnan,Department of Physics,The Cochin College, Kochi.

N. Ibohal,Department of Mathematics,University of Manipur, Imphal.

S.S.R. Inbanathan,Department of Physics,The American College, Madurai.

Deepak Jain,Deen Dayal Upadhyaya College, Delhi.

Sanjay Jain,Guru Premsukh Memorial College of Engg., Delhi.

7

Chanda Jog,Department of Physics,Indian Institute of Science, Bangalore.

Moncy John,Department of Physics,St. Thomas College, Kozhencherri.

Kanti Jotania,Department of Physics,The M.S. University of Baroda, Vadodra.

R.S. Kaushal,Department of Physics,Ramjas College, Delhi.

Manoranjan Khan,Centre for Plasma Studies, Faculty of Sciences,Jadavpur University, Kokata.

Pushpa Khare,Department of Physics,Utkal University, Bhubaneswar.

Nagendra Kumar,Department of Mathematics,K.G.K. (PG) College, Moradabad.

A.C. Kumbharkhane,School of Physical Sciences,Swami Ramanand Teerth Marathwada University,Nanded.

V.C. Kuriakose,Department of Physics,Cochin University of Science and Technology, Kochi.

Daksh Lohiya,Department of Physics and Astrophysics,University of Delhi.

Ashok Kumar Mittal,Department of Physics,University of Allahabad.

S. Mukherjee,Department of Physics,North Bengal University, Siliguri.

K.K. Nandi,Department of Mathematics,North Bengal University, Siliguri.

Udit Narain,Astrophysics Research Group,Meerut College.

S.K. Pandey,School of Studies in Physics,Pt. Ravishankar Shukla University, Raipur.

Sanjay Pandey,Department of Mathematics,L.B.S.P.G. College, Gonda.

U.S. Pandey,Department of Physics,D.D.U. Gorakhpur University.

P.N. Pandita,Department of Physics,North Eastern Hill University, Shillong.

K.D. Patil,Department of Mathematics,B.D. College of Engineering, Sevagram.

M.K. Patil,School of Physical Sciences,Swami Ramanand Teerth Marathwada University,Nanded.

B.C. Paul,Department of Physics,North Bengal University, Siliguri.

Ninan Sajeeth Philip,Department of Physics,St. Thomas College, Kozhencherri.

Anirudh Pradhan,Department of Mathematics,Hindu P.G. College, Zamania.

Lalan Prasad,Department of Physics,M.B. Govt. P.G. College, Haldwani.

T. Ramesh Babu,Department of Physics,Cochin University of Science and Tech., Kochi.

S. Rastogi,Department of Physics,D.D.U. Gorakhpur University.

Saibal Ray,Department of Physics,Barasat Government College.

R. Ramakrishna Reddy,Department of Physics,Sri Krishnadevaraya University, Anantapur.

Sandeep Sahijpal,

8

Department of Physics,Punjab University, Chandigarh.

Asoke Kumar Sen,Department of Physics,Assam University, Silchar.

T.R. Seshadri,Department of Physics and Astrophysics,University of Delhi.

K. Shanthi,Academic Staff College,University of Mumbai.

G.P. Singh,Department of Mathematics,Visvesvaraya National Institute of Tech., Nagpur.

H.P. Singh,Department of Physics and Astrophysics,University of Delhi.

Santokh Singh,Department of Physics,Deshbandhu College, Delhi.

Yugindro Singh,Department of Physics,Manipur University, Imphal.

D.C. Srivastava,Department of Physics,D.D.U. Gorakhpur University.

Pradeep K. Srivastava,Department of Physics,D.A.V. P.G. College, Kanpur.

P.K. Suresh,School of Physics,University of Hyderabad.

R.S. Tikekar,Department of Mathematics,Sardar Patel University, Vallabh Vidyanagar.

A.A. Usmani,Department of Physics,Aligarh Muslim University.

J.P. Vishwakarma,Department of Mathematics and Statistics,D.D.U. Gorakhpur University.

Till June 30, 2005

Z. Ahsan,

Department of Mathematics,Aligarh Muslim University.

Rashmi Bhardwaj,Department of Mathematics,Guru Gobind Singh Indraprastha University, Delhi.

S.P. Bhatnagar,Department of Physics,Bhavnagar University.

Satyabrata Biswas,Department of Physics,University of Kalyani.

Somenath Chakrabarty,Department of Physics,University of Kalyani.

D.K. Chakraborty,School of Studies in Physics,Pt. Ravishankar Shukla University, Raipur.

P.P. Hallan,Department of Mathematics,Zakir Husain College, Delhi.

S.N. Hasan,Department of Astronomy,Osmania University, Hyderabad.

K. Indulekha,Department of Physics,Mahatma Gandhi University, Kottayam.

Usha Malik,Department of Physics,Miranda House, Delhi.

K.K. Mondal,Department of Physics,Raja Peary Mohan College, Hooghly.

S.K. Popalghat,Department of Physics,J.E.S. College, Jalna.

P. Vivekananda Rao,Department of Astronomy,Osmania University, Hyderabad.

L.M. Saha,Department of Mathematics,Zakir Husain College, New Delhi.

R.V. Saraykar,Department of Mathematics,Nagpur University.

9

Bhim Prasad Sarmah,Department of Mathematical Sciences,Tezpur University.

Rajendra Shelke,Space Research Centre,Amravati.

R.C. Verma,Department of Physics,Punjabi University, Patiala.

From July 1, 2005

A. Bhattacharya, (upto February 28, 2006)Department of Physics,St. Xavier’s College, Kolkata.

Asis Kumar Chattopadhyay,Department of Statistics,Calcutta University.

Rabin Kumar Chhetri,Sikkim Government College, Gangtok.

Ujjal Debnath,Department of Mathematics,Bengal Engineering and Science University, Howrah.

Alok Kumar Durgapal,Department of Physics,Kumaun University, Nainital.

Naveen Gaur,Department of Physics,Dyal Singh College, New Delhi.

P.S. Goraya,Department of Physics,Punjabi University, Patiala.

Naseer Iqbal Bhat,PG Department of Physics,University of Kashmir, Srinagar.

Pradip Mukherjee,Department of Physics,Presidency College, Kolkata.

C. Mukku,International Institute of Information Technology,Hyderabad.

Nagalakshmi Rao,Department of Physics,Government Science College, Bangalore.

E. Saikia,Department of Physics,Inderprastha Engineering College, Ghaziabad.

Pankaj Kumar Shrivastava,Department of Physics,Government Model Science College, Rewa.

10

The sixteenth batch of Visiting Associates, who were selectedfor a tenure of three years, beginning July 1, 2005.

Nagalakshmi A. Rao

Rabin Chhetri

Pradip Mukherjee Pankaj Kumar Shrivastava

Ujjal Debnath

The photographs of the following Visiting Associates from the sixteenth batch are not available: Alok Kumar Durgapal,Naveen Gaur, C. Mukku and E. Saikia.

Appointments of the following Visiting Associates from the thirteenth batch were extended for three years : G. Ambika,Narayan Banerjee, Subenoy Chakraborty, Sarbeshwar Chaudhuri, Sushant G. Ghosh, K.P. Harikrishnan, Chanda J. Jog,Kanti R. Jotania, R.S. Kaushal, Nagendra Kumar, Yogesh Kumar Mathur, Kamal Kanti Nandi, P.N. Pandita, Harinder PalSingh, K. Yugindro Singh, D.C. Srivastava, Pradeep Kumar Srivastava and Anisul Ain Usmani.

Abhijit Bhattacharya

P.S. Goraya Naseer Iqbal

Asis K. Chattopadhyay

11

Dean, Core Academic Programmes(T. Padmanabhan)

Head, Pedagogical Programmes(K. Subramanian)

Head, Computer Centre(A.K. Kembhavi)

Head, Library and Publications(T. Padmanabhan)

Head, Instrumentation / Telescope(A. N. Ramaprakash)

Organizational Structure ofIUCAA's Academic Programmes

The Director

N.K. Dadhich

Dean, Visitor Academic Programmes(A.K. Kembhavi)

Head, Infrastructural Facilities(A.K. Kembhavi)

Head, Meetings and Visitors(N.K. Dadhich)

Head, Public Outreach Programmes(R. Misra)

Head, Recreation Centre(P. Chordia)

Head, Guest Observer Programmes(R. Srianand)

12

The Director's Report

The highlight of the year was successful completion ofthe Telescope project. The telescope was successfullyinstalled and commissioned with all the required testsmeeting the specification and it was finally handed overto IUCAA by PPARC/TTL in February 2006. Though theproject was quite delayed due to various reasons, it wasgratifying to see that we had ultimately got a very finetelescope which had so far performed better than ourexpectation.

An instrument of this kind is indeed a very complex andchallenging endeavour involving very exacting demandson various aspects of engineering, optics, software andlogistics. It is a tribute to the TTL team and ourinstrumentation as well as administrative support teamsfor the job well done. Particularly they had combinedand resonated beautifully in installation andcommissioning of the telescope. I greatly appreciate Mr.Jeff Down of PPARC and Dr. Paul Rees of TTL for theunderstanding and concern they brought upon forcompletion of the project. I thank them all warmly.

With the telescope in place and functioning, it is wonderfulto see a bubbling observational group crystalizing.Suddenly the air around tea tables breathes of spectrumand arc-seconds rather than dark energy andHamiltonians. I hope it will have a similar effect on theuniversity colleagues and there would be a welcomeemergence of observational activity in the universities.

The telescope will be a good optical compliment toNCRA’s Giant Metrewave Radio Telescope and the twotogether will form a strong astronomical axis in thecountry.

As a tribute as well as an inspiring and motivating forcefor young students, we have made documentary films incollaboration with Vigyan Prasar (DST, Delhi) on the twolegendary academics and Honorary Fellows of IUCAA,Professors A.K. Raychaudhuri and P.C. Vaidya, whosymbolized excellence in teaching and research inuniversities. The films have been widely circulated andgreatly admired.

It is very unfortunate that Professor Raychaudhuri couldnot see the finished film as he suddenly passed away onJune 18, 2005, shortly after the shooting of the film wasover. Ever since the conception of IUCAA, he was agreat source of inspiration and support. In his demise wehave truly lost a friend, philosopher and guide. On behalfof IUCAA family and on my personal behalf, I pay deepestand warmest homage to him and to what he meant to allof us.

We have also made a 12 minute flyer film, “Joy and Truthof Science”, on the activities of the Science Centre,Muktangan Vidnyan Shodhika, which is also circulatedwidely and is greatly appreciated. I hope that thisexperiment of learning and enjoying science through toyswill spread in schools all around far and wide.

The Scientific Advisory Committee of IUCAA visited usduring January 3-7, 2006. As usual, they reviewed allour programmes and activities and then made a detailedreport. One of the main recommendations was to openIUCAA to visitors from universities outside India. TheCommittee expressed its unqualified admiration for thework being done at IUCAA and full satisfaction on itsperformance on various fronts. In particular, it was veryappreciative of dedication and commitment exhibited byour administrative and support staff, and Professor AbhayAshtekar, who has seen IUCAA growing right from itsconception, wrote "....It has been a pure joy to see howwell the Institute has blossomed to become a stronginternational presence over a relatively short period oftime. A lot of the credit goes to the vision of its FoundingDirector, Professor J. V. Narlikar and there was someconcern about what would happen after he retired. Thefact that IUCAA has remained so robust and hascontinued to rise is largely due to the sense of dedicationand pride everyone has. It is very rare to see this spirit-- especially among the administrative staff. On behalfof the international community, I would like to thankall the staff......"

Professor Arun Nigavekar who was the Chairperson ofUGC as well as President of IUCAA Council, demited theoffice in September 2005 on completion of his term. Ithank him warmly for his guidance and support allthrough and particularly for the understanding andsupport shown by him for the telescope project at a verycritical juncture. He is a good friend of long standing andit is wonderful to have him back in Pune, which is indeedassuring.

I extend a very warm welcome to Professor S. K. Thorat,who has assumed office of Chairperson, UGC andthereby President of IUCAA Council in February 2006. Ilook forward to his guidance and wise counsel. I wouldlike to assure him that IUCAA would as before continueto provide a resource base for scientific and educationalprogrammes of national importance.

Naresh Dadhich

13

Congratulations to ...

Ajit Kembhavi

UGC National Hari Om Ashram Trust Award - Outstanding Social Scientist/ Scientist for interaction between Scienceand Society for the year 2004.

J. V. Narlikar

Mohamed Sahabdeen Award for Science (2004) from the A.M.M. Sahabdeen Trust Foundation, Sri Lanka, June 28,2005.

Vikram Sarabhai Lifetime Achievement Award (2004) from the Consortium for Educational Communication (CEC),New Delhi, September 16, 2005.

Doctor of Science (Honoris Causa) from the Hemwati Nandan Bahuguna Garhwal University, Srinagar, Garhwal,October 16, 2005.

Jeevangaurav Puraskar from the Chaturang Pratisthan, Mumbai, October 30, 2005.

T. Padmanabhan

Elected to International Union of Pure and Applied Physics, Commission 19 [Astrophysics].

Received a Honorable Mention in the Gravity Research Foundation Essay contest, 2005, for his essay "A newperspective on Gravity and the dynamics of Spacetime”.

14

Calendar of Events

2005

April 18-May 27 School Students’ Summer Programmeat IUCAA

May 6 IUCAA-NCRA Graduate SchoolSecond semester ends

May 16-June 17 Refresher Course in Astronomy and Astrophysics for Collegeand University Teachersat IUCAA

May 16-July1 Vacation Students’ Programmeat IUCAA

August 8 IUCAA-NCRA Graduate SchoolFirst semester begins

August 7-8 Introductory Workshop: From Stars to the Universeat University of Calicut, Kozhikode

August 29-31 Workshop on Observing Projects with Small Telescopesat IUCAA.

November 21-23 Introductory Workshop: Sun and Starsat St. Xavier’s College, Kolkata

November 29- Young Astronomers’ Meet (YAM 2005)December 2 at IUCAA

December 5-7 Introductory Workshop: Instruments and Observationsat Karnataka University, Dharwad

December 9 IUCAA-NCRA Graduate SchoolFirst Semester ends

December 15-22 International Conference on Einstein’s Legacy in the New Millenniumat Toshali Sands, Puri, Orissa(Organized jointly by IUCAA; IOP, Bhubaneshwar andDepartment of Physics, Utkal University, Bhubaneshwar)

December 21-23 Workshop on Astrostatisticsat Calcutta University, Kolkata

December 26 School on Cosmology and Very Early Universe(Dedicated to the memory of A.K. Raychaudhuri)at IUCAA)

December 29 Foundation Day

2006

January 2 IUCAA-NCRA Graduate SchoolSecond semester begins

February 28 National Science Dayat IUCAA

ACADEMIC PROGRAMMES

The following description relates to research workcarried out at IUCAA by the Core Academic Staff,Post-Doctoral Fellows, and Research Scholars. Thenext section describes the research work carried outby Visiting Associates of IUCAA using the Centre’sfacilities.

(I) RESEARCH BY

RESIDENT MEMBERS

The research described below is grouped area-wise.The name of the concerned IUCAA member ap-pears in italics.

Quantum Theory and Gravity

Holographic framework for semiclas-sical gravity

The elegance of general relativistic description ofgravity rests on the geometric structure, which inturn is based on the Principle of Equivalence. Inits simplest form, principle of equivalence allowsthe description of gravity in terms of a metric ten-sor and determines the kinematics of gravity (‘howgravity tells matter to move’) by invoking specialrelativity in the local inertial frames.

Contrast this with the description of dynamicsof gravity (‘how matter tells spacetime to curve’)for which we completely lack a similar guiding prin-ciple. Classical dynamics has to arise from semi-classical limit of quantum gravity through the vari-ation of the semiclassical action functional. But welack a guiding principle to choose such an actionfunctional! There are several serious issues whichcrop up when we try to determine the action func-tional:

• If gab are the dynamical variables, the naturalaction functional should be quadratic in thederivatives ∂g of gab. But principle of equiv-alence — which allows us to reduce gab →ηab, ∂cgab → 0 in any local region — preventsthe existence of such a generally covariant ac-tion. So, general covariance, combined withprinciple of equivalence, forces us to include∂2g terms in the action; but then the varia-tional principle becomes ill-defined and needsa special treatment. This situation is unparal-leled in any other theory in physics like, e.g.,Yang-Mills models.

• Further, any such action can only provide alow energy effective description of gravity. Thesemiclassical theory is likely to exist in some D

dimensional spacetime with D > 4 and quan-tum corrections will add higher order correc-tion terms involving squares of the curvatureetc. We have no guiding principle or symmetryto determine these higher order terms.

A closely related question is: What are thetrue degrees of freedom of gravity? The descrip-tion in terms of gab may be most geometrical butit is highly gauge redundant. Any description interms of an alternative set of variables has impor-tant conceptual implications for dynamics — espe-cially for the problem of the cosmological constant.For example, if the degrees of freedom of gravityin a spatial volume V scale as the area S of thebounding surface rather than the volume, then thebulk cosmological constant cannot produce gravi-tational effects. The reduction from volume to areachanges the energy density of the vacuum, that is,coupled to gravity from the gigantic L−4

P to the ob-served value L−4

P (L2P /S) with S ≈ H−2, as shown

by T. Padmanabhan a few years back.More recently, Padmanabhan has produced a

paradigm in which all the above issues can be suc-cessfully tackled at one go.

In particular, he shows that theories whichobey principle of equivalence and general covari-ance have a generic structure for their low energyaction functional, using which one can systemat-ically obtain corrections to classical gravity. Heproves that the (a) principle of equivalence, (b) gen-eral covariance and (c) the demand that the varia-tion of the action functional should be well defined,lead to a generic Lagrangian for semiclassical grav-ity of the form L = Q bcd

a Rabcd with ∇b Q bcd

a = 0.The expansion of Q bcd

a in terms of the derivativesof the metric tensor determines the structure of thetheory uniquely. When the action is expanded inthe powers of curvature, one obtains the Einstein-Hilbert (EH) action as the unique zero-order termalong with Gauss-Bonnet (GB) type correction asthe unique first-order term. What is probably evenmore remarkable is that all these action functionalsallow a natural, holographically dual, description;that is, the action functional can be expressed as asum of bulk and surface terms with a definite rela-tionship between the two. The gauge redundancyof geometric description therefore allows all thesetheories to be described entirely in terms of surfacedegrees of freedom, thereby, suggesting a naturalsolution to the cosmological constant problem.

Further, just as in the case of EH action, itis possible to reformulate the theory retaining onlythe surface term for the gravity sector. If we con-sider an action principle based on (Am +As) whereAm is the matter action and As is the action ob-tained from −Lsur then, for variations that arisefrom displacement of a horizon normal to itself,

15

one gets the equation (Eab − 12Tab)ξbξa = 0, where

ξa is a null vector. Combined with the (gener-alised Bianchi) identity ∇aEab = 0 this will leadto standard field equations with a cosmologicalterm Eab = (1/2)Tab + Λgab just as in the caseof Einstein-Hilbert action.

In this approach, which uses only surface de-grees of freedom for gravity, the basic field equa-tions are (Eab − 1

2Tab)ξbξa = 0, where ξa is a nullvector. So the addition of a cosmological constant— by the change Tab → Tab + Λgab — leaves theequations invariant. Gravity ignores the bulk vac-uum energy density! When generalised Bianchiidentity is used, the cosmological constant doesarise as an integration constant; but now, it canbe set to any value as a feature of the solution tothe field equations. It has a status similar to massin the Schwarzschild metric. This provides a basicreason for ignoring the bulk cosmological constantand its changes during various phase transitions inthe universe. The thermodynamic paradigm alsoimpies that if an observer has a horizon, we shouldwork with the degrees of freedom confined by thehorizon. This changes the pattern of vacuum fluc-tuations and leads to the correct, observed valueof the cosmological constant, as mentioned before.These features arise purely from principle of equiv-alence and general covariance and is not specific toEinstein’s theory. Any theory of gravity describedby a metric will have similar features and hencehigher order quantum gravitational corrections arelikely to respect these principles.

Casimir effect confronts the cosmolog-ical constant

According to the uncertainty principle of quantummechanics, any quantum system is subject to fluc-tuations, even in the ground state. The vacuum ofany quantum field is thus far from empty, and hasa non-zero energy (E0), which can be obtained bysumming over the zero-point energies of the entirespectrum of field modes. When non-trivial bound-ary conditions (∂Γ) are imposed on the field, thezero-point fluctuations of the vacuum get modified,leading to a finite shift in energy to some othervalue E[∂Γ] given by ΔE = E[∂Γ] − E0. A realis-tic example of this is the perturbation of the elec-tromagnetic field due to the presence of metallicbodies. This change in the vacuum energy, ΔE,manifests as a tangible force between the macro-scopic bodies, which distort the vacuum. This phe-nomenon, known as the Casimir effect, is one ofthe remarkable observable consequences of the ex-istence of quantum vacuum fluctuations. A well-studied example is the case of two neutral, per-fectly conducting parallel plates; in free space, the

spectrum of possible wave modes of the vacuumforms a continuum, but the presence of plates re-stricts the normal components of the allowed wavemodes between them to discrete values. This dis-creteness leads to a finite lowering of the vacuumenergy, resulting in a force of attraction . In (3 +1)dimensions, the force per unit area has the form

F (a)A

= − π2

240hc

a4(1)

where a denotes the plate separation. The exis-tence of this force has been verified to a high degreeof precision in several laboratory experiments overthe past decade.

Both the quantities E[∂Γ] and E0 are for-mally divergent. In order to extract a finite dif-ference, a suitable regularization procedure has tobe adopted. One such method involves introducingan ultraviolet cut-off function that suppresses thecontribution of the high-frequency modes and ren-ders the difference well-defined, and then, at theend of the calculation, letting the cut-off frequencygo to infinity to obtain a finite result, that turnsout to be independent of the functional form of thecut-off.

Any modification of the intrinsic spectrum ofzero-point quantum fluctuations will also leave animprint on the Casimir effect. In particular, if thereexists a cut-off length Lc in nature, due to someunknown physics, it would act as a natural UVregulator, suppressing the field modes with wave-lengths λ � Lc and leading to a modification ofthe Casimir force between bodies. In the case ofparallel plates separated by a distance a, for ex-ample, the maximum wavelength allowed betweenthem is λmax ∼ 2a, and it is the modes with wave-lengths lying in the range Lc � λ � 2a, whichwill contribute to the Casimir effect. This is indis-tinguishable from the standard result, if Lc � a,which is usually the case since the cut-off lengthssuggested in the literature are usually of the orderof Planck length. But if this cut-off length is signifi-cantly larger, there would be significant correctionsto the standard result when Lc � a. Presently,there is a strong experimental evidence for the elec-tromagnetic Casimir force between metallic bod-ies up to separations around 100 nm and no sig-nificant deviations from the predicted results havebeen observed. This suggests that any possible cut-off length scale Lc must lie below this value. Thistranslates into a lower bound on the vacuum energydensity of ρV � 1 (eV )4.

There are some proposals in the literature thatthe zero-point energy of vacuum — made finite bya cut-off — may contribute to gravity and leadto a non-vanishing cosmological constant respon-sible for the currently observed accelerated expan-

16

sion of the universe. Current cosmological obser-vations seem to favour a cosmological constant asthe candidate for dark energy and constrain theenergy density contributed by it to be roughlyρDE ≈ 10−11(eV )4, with a corresponding lengthscale of the order of 0.1 mm. The significant dis-crepancy of this value with the bound obtainedfrom the Casimir effect measurements, makes it un-likely that the cosmological constant has anythingto do with zero-point energy rendered finite by acut-off of unknown physical origin but having thecorrect length scale.

Gaurang Mahajan, Sudipta Sarkar and T.Padmanabhan have recently performed a detailedanalysis of this issue by studying the effect of sucha cut-off on the behaviour of the Casimir force be-tween parallel conducting plates. By assuming thatthe presence of this cut-off manifests through mod-ification of the dispersion relation for field modes,they show that it can significantly alter the stan-dard result, and even lead to repulsive Casimirforce when the plate separation is smaller than thecut-off scale length. On the basis of current lab-oratory data, they conclude that any such cut-off,which is consistent with the observed Casimir ef-fect will lead to an energy density at least about1012 times larger than the presently observed valueof the cosmological constant driving the acceler-ated expansion of the universe, if gravity couplesto these modes. This invalidates the recently pro-posed idea that the observed cosmological constantmay arise from the zero-point energy made finite bya suitable cut-off.

Classical Gravity

Gravity is one of the fundamental forces of nature,but it distinguishes itself from the others by be-ing universal. It links and affects all that physi-cally exists in the universe, and it is present every-where and is unshieldable. This remarkable char-acter puts it on a different pedastal. It is, therefore,understandable that its dynamics and descriptionmay be different from the other forces.

Einstein was the first to bring out the first dif-ference and showed that gravity could truly be de-scribed by curvature of spacetime itself. No otherforce makes such a demand on spacetime. Ein-stein’s theory of gravitation, known as general rela-tivity, imbibes this feature and Einstein’s equationis valid in all dimensions, n ≥ 2.

Next question arises, in how many dimensionsshould gravity live? It turns out that 2 and 3 di-mensions are not big enough to let gravity pro-pogate from one point in space to the other. Soone is led to the usual 4 dimensional spacetime.

Does gravity remain confined to 4 dimensions? Thesource for gravity is matter/energy distributionwhich generally lives in 3 dimensional space. Grav-ity is self interactive, it interacts with itself. Selfinteraction can only be evaluated iteratively. Thefirst iteration is, however, included in Einstein’sequation through square of first derivative of themetric.

How does one go beyond the first? This couldbe achieved by inclusion of a specific combination ofsquare of Riemann, Ricci and Ricci scalar, knownas Gauss-Bonnet term, in the action. But this termmakes no contribution to Einstein equation in di-mensions, n < 5. Thus, we have to go to higherdimensions to realise second iteration of self inter-action. As 2 and 3 dimsnions are not big enoughto accommodate propagation of gravity, similarly4 dimension is not sufficient for its self interaction.This is purely a classical consideration and moti-vation for higher dimensions. On the other hand,string theory, which is one of the attempts for quan-tum theory of gravity, necessarily requires higherdiemsnions for its formulation.

Gauss-Bonnet gravity (GB) has been N.K.Dadhich’s main concern. It turns out the genericfeature of GB is to weaken black hole singularity inhigher dimensional black hole. It would be interest-ing to bring these desirable properties through dila-ton coupling and suitable choice of topology downto the 4 dimensional universe we live in. There aresome encouraging indications in this direction.

Gravitational Waves

The existence of gravitational waves (GWs), pre-dicted in the theory of general relativity, has longbeen verified indirectly through the observationsof Hulse and Taylor. The inspiral of the mem-bers of the binary pulsar system named after themhas been successfully accounted for in terms ofthe back-reaction due to the radiated GW. How-ever, detecting such waves with man-made ‘anten-nas’ has not been possible so far. Nevertheless,this problem has received a lot of attention in thepast several years, especially, due to the arrival oflaser-interferometric detectors, which are expectedto have sensitivities close to that required for de-tecting such waves. Most of the interferometric de-tectors are either taking science data or nearingoperation. Detailed description of the detectors aswell as detection techniques have been given in pre-vious annual reports.

17

Obtaining the gravitational wave skymap of the stochastic background

The gravitational wave background can arise froma variety of sources. Not all GW sources havewell modelled signals. Supernovae with asymmetriccore collapse and binary black hole (BBH) merg-ers can be very strong sources of GWs. In ad-dition to the above objects, GWs from low-massX-ray binaries (LMXBs) and hydrodynamical in-stabilities in neutron stars (r-modes) will be ob-servable by earth-based detectors like LIGO. Butthe waveforms of none of these objects is well un-derstood. This is a subject of active investigationamong numerical relativists. While currently sug-gested waveforms will be used for matched-filteringthe data, the dismissal rates of such searches canbe extremely high owing to the imperfect nature ofthese waveforms. Such a situation requires the ex-ploration of other search statistics that are optimal(with minimum false dismissal rate for a given falsealarm rate) when the knowledge of the waveformsis incomplete. Moreover, LIGO-type detectors willlikely observe GWs from astrophysical objects thatwe never knew existed.

Individually, the above mentioned sources canbe categorized as short-duration, e.g., SN core col-lapse, BBH merger, and r-modes, or long-duration,viz., LMXBs. On the other hand, when a collec-tion of any subset of these sources is unresolvable,it can appear as a stochastic GW background of avariable duration in our detectors of interest.

The signal from the unmodelled sources willnot typically stand above the broadband noise ofthe interferometric detectors; the concept of an ab-solutely certain detection does not exist in sucha case. Only probabilities can be assigned to thepresence of an expected signal. In the absence ofprior probabilities, such a situation demands a de-cision strategy that maximizes the detection proba-bility for a given false alarm probability. Maximumlikelihood methods will be explored to obtain theoptimal network statistic for detecting excess GWpower. Apart from this, the fundamental aspectsof the formalism required for creating a sky-map ofthe astrophysical/cosmological gravitational wavebackground arising from a host of unmodelled orunresolved sources while using the full potential ofthe operating network of detectors by coherentlycombining their data.

The formulation of the problem of mappingthe gravitational-wave sky has three critical ele-ments: (a) Measuring the excess power per pixel,(b) estimating the GW background per pixel afterdeconvolution of the synthesized network antenna-pattern from the data, and (c) Testing the “searchand map” algorithm on simulations.

The raw sky map of the GW background isthe signal convolved with the antennae pattern.We must invert this equation in order to obtainthe GW power from each direction. For this pur-pose, theoretical analysis of the excess power ker-nel has been undertaken, which will indicate to usthe appropriate method of inversion. Dependingon whether the kernel is non-degenerate or degen-erate, either matrix inversion or maximum entropyor Richardson-Lucy type of methods will be em-ployed. From IUCAA, Sanjit Mitra, Sanjeev Dhu-randhar and Tarun Souradeep are involved in thiswork.

This is the gist of the Indo-US proposal withA. Lazzarini of Caltech and S. Bose of WSU whichhas been submitted to DST and NSF. Sanjit Mitraand S. V. Dhurandhar have analysed the kernel ofthe integral equation by means of the stationaryphase method. The method gives a rough estimateof the kernel and the result could be used towards afirst guess for the solution, which is then obtainediteratively by numerical means. The kernel or thepoint spread function for a typical point source isshown in Figure (1) on the left of the figure, whilethe right hand side of the figure depicts the station-ary phase approximation - the point source spreadsinto a figure of eight.

This work should also benefit two othersearches. First, since the long-duration integra-tion of the data will essentially comprise a sumover short stretches, a large signal in a shortstretch will constitute a candidate for a transientor burst (short-duration) event. Unlike the coin-cidence search being currently conducted for suchevents, this work will combine coherently the out-puts of several detectors and, thus, improve theirdetectability.

Second, the long-duration integration of thedata should be able to find gravitational wave sig-nals from modelled sources, such as pulsars. Al-though this method is optimal for searching un-modelled sources, it is not so for pulsars, the signalsfrom which can be matched filtered. The prob-lem with the latter method is that owing to thevery large parameter space volume, an all-sky, all-frequency search for pulsars with matched filter-ing is not computationally viable. This method isnot handicapped by this problem, since it does notuse the intrinsic source parameters for the search;rather it uses the data from one detector to ‘filter’that from others in the network, after appropriatelytime-shifting them and weighing them with the re-spective antenna patterns. Thus, our method canbe used as the first step in a two-step hierarchicalsearch for pulsars, where triggers from our methodare followed up with matched filtering.

This project pursued at IUCAA is especially

18

Figure 1: On the left, the kernel or the point spread function is shown for a source on the equator for the two LIGO detectorsat Hanford and Louisiana in the US, for which a bandwidth of a kHz is assumed. On the right is shown the kernel obtainedfrom the stationary phase approximation.

important, because it will obtain the best everbounds on the strengths of gravitational wavesfrom unmodelled sources while using the full po-tential of the operating network of detectors by co-herently combining their data. Such a combinationwill account for the time-varying network antennapatterns as well as the relative shifts in the phaseof a gravitational wave at the different detectors.It will also be able to detect a stochastic astro-physical GW background, which might arise froma superposition of a large number of independentand unresolved GW sources. If excess power is de-tected in certain patches of the sky, then the toolsdeveloped will be used to construct the GW mapof those regions of the sky. When integrated overtime, these excess powers in different time segmentswill add up to give the physical equivalent of theenergy captured by the network from a given patchin the sky.

The usefulness of this work cannot be un-derestimated in the cosmological context either.There exist alternative cosmological models (e.g.,the string-inspired pre-big-bang model) that pre-dict a stochastic cosmological GW background thatshould be detectable by Advanced LIGO. If any ofthese models is found to be borne out by observa-tions, then the sky-map construction given abovecan, in principle, be used to seek any anisotropies(including a possible dipole component) in it. Thisprocess in turn can unravel useful clues on how theuniverse began. On the other hand, an astrophysi-cal background will provide information about ourimmediate neighbourhood.

Coherent versus coincidence searchfor inspiraling binaries

The coherent search strategy uses the maximumlikelihood method, where a single likelihood ra-tio for the entire network - that is, the networkis treated as a single detector. This is similar toaperture synthesis being carried out, for example,by radio astronomers. The likelihood method com-bines the data from a network of detectors in aphase coherent manner to yield a single statistic,which is optimal in a given sense. This statistic isthen compared with the threshold determined bythe false alarm rate that we are prepared to tol-erate. If the statistic crosses the threshold, thena detection is announced. Note that a single like-lihood ratio is computed and a single threshold isapplied in this type of search.

On the other hand, the coincidence approachinvolves separately filtering the signal in each detec-tor, applying two separate thresholds correspond-ing to each detector and preparing two event listsdetermined by the crossings. Then the event listsare matched if the estimated parameters for theevents lie in a reasonable neighbourhood in the pa-rameter space of signals. A detection is registeredif the differences in the estimated parameters liewithin certain bounds - that is, the parameters ofthe events must lie within a certain ‘window’ of theparameter space.

H. Mukhopadhyay, S.V. Dhurandhar, N. Sago,H. Tagoshi and N. Kanda are comparing the twoapproaches by plotting the Receiver OperatingCharacterstic (ROC) curves. The simplest and

19

1e-90 1e-80 1e-70 1e-60 1e-50P

FA (False Alarm)

0

0.2

0.4

0.6

0.8

1

P DE

(D

etec

tion

Efi

icie

ncy)

single(simulation)single(analytic)coincident(simulation)coincident(analytic)coherent(analytic)coherent(simulation)

Figure 2: ROC curves are shown for two identical LIGO type detectors in the same location with the same orientation andhaving the same power spectral density of noise when coherent and coincident detection criteria are used. Coherent detectionis substantially a better approach as seen from the curves.

the worst scenario case (from the point of viewof the coherent search) is being investigated, inwhich two identical detectors are considered in thesame location and the same orientation. Analyti-cal results and Monte-Carlo simulations are beingused to quantify the performance of the two meth-ods. The ROC consists of plotting the false dis-missal (or equivalently detection probability) ver-sus the false alarm. The higher the false dismissalfor a given false alarm, the better the performanceof the method. The Indian team consisting ofH. Mukhopadhyay and S. Dhurandhar have beeninvolved in the simulations of plotting the ROCcurves based on analytics given by the Japaneseand then comparing the results. A slightly moregeneral case has been considered, where the detec-tors may not have the same orientations, but oth-erwise are identical and coincident. The two ap-proaches are being tested using Gaussian station-ary noise with the noise power spectral density ofadvanced detectors. Figure (2) shows that the co-herent method is far superior to the coincident onejustifying the extra computational cost.

DuringS.V. Dhurandhar’s visit to Osaka, thecase of two detectors can have correlated noise hasbeen also investigated. It remains to perform simu-lations to validate the analytical results. This workwill be extended to a network of several detectorshaving arbitrary locations and orientations. Thiswork comes under the Indo-Japanese collaborationand has been funded by DST (India) and JSPS(Japan).

A general relativistic analysis of LISAdynamics and optics

The joint NASA-ESA mission LISA relies cruciallyon the stability of the three spacecraft constella-tion. Each of the spacecraft is in heliocentric or-bits forming a stable triangle. In order for LISAto operate successfully, it is crucial that the threespacecraft which form the hubs of the laser inter-ferometer in space maintain nearly constant dis-tances between them. The distance between anytwo spacecraft is ∼ 5 × 106 km, which must bemaintained during the LISA’s flight. However, inorder to thoroughly study optical links and lightpropagation between these moving stations, onerequires detailed analysis of the LISA configura-tion. S. V. Dhurandhar, R. Nayak, S. Koshti andJ-Y Vinet have examined the principles of a stableformation flight and also presented an analyticaltreatment of the problem in the context of LISA.They first study three Keplerian orbits around theSun with small eccentricities and optimise the or-bital elements so that the spacecraft form an equi-lateral triangle with nearly constant distances be-tween them.

LISA sensitivity is limited by several noisesources. A major noise source is the laser frequency(phase) noise, which is expected to be several or-ders of magnitude larger than other noises in theinstrument. Thus, cancelling the laser frequencynoise is vital to LISA for attaining the requisitesensitivity.

A systematic method based on modules overpolynomial rings was given S. V. Dhurandhar, R.Nayak and J-Y Vinet. The method guarantees

20

all the data combinations, which cancel the laserfrequency noise. The data combinations consistof suitably delayed data streams added togetherto produce data streams free from laser frequencynoise. These noise free data streams constitute themodule of syzygies. However, this problem hasbeen solved with the assumptions that LISA is sta-tionary and has essentially constant arm-lengths.This approach needs to be generalised to the re-alistic motion of LISA, where the LISA trianglerotates about its centre - which leads the Sagnaceffect, which must be accounted for - and where thelaser light rays follow null geodesics in the back-ground gravitational field mainly produced by theSun.

The first goal was to analyse the motion ofLISA spacecraft with a view to determine thosespacecraft configurations, which are stable from thepoint of view of laser frequency noise cancellation.With this goal in mind, R. Nayak, S. Koshti, S.V.Dhurandhar and J-Y Vinet have analysed the mo-tion of the spacecraft to octupole order of the Sun’sgravitational field. It is further shown that thislevel of approximation gives near exact results byperforming relevant numerical computations. Alsothe stablest configurations of LISA have been de-termined within the scope of this model by varyingthe orbital elements of the spacecraft orbits.

The next goal is to determine the optical links -the path lengths - between spacecraft in the Sun’sfield taken to be Schwarzschild and compute thephase development of the laser beam along a nullgeodesic. This approach automatically takes intoaccount the special and general relativistic effectswhich have so far been estimated in an adhoc man-ner and perhaps with substantial errors. Such ef-fects are (i) the Sagnac effect because of the ro-tation of the LISA constellation, (ii) gravitationalred-shift, (iii) Shapiro effect, etc. The final goal isto determine the data combinations cancelling laserfrequency noise taking into account the general rel-ativistic model of LISA so that the LISA simulatorcan be built based upon this complete model. Thisis the work proposed in the Indo-French project,which has been cleared and should begin in thenear future.

Cosmology and Structure For-mation

Higher dimensional cosmology

Varun Sahni and Yuri Shtanov have studied somecosmological consequences of extra dimensions.Higher dimensional cosmology has had an impres-

sive history ever since Kaluza and Klein’s pioneer-ing efforts to unify the laws of gravitation and elec-tromagnetism within a single five dimensional set-ting. In the Kaluza-Klein approach, the extra di-mensions were assumed to be ‘curled up’ and small.An alternative to this approach of hiding extra di-mensions by curling them to sufficiently small radiiis the braneworld paradigm, according to which, ouruniverse is a submanifold, or slice, of a higher di-mensional space-time. In contrast to KK compact-ification in which the extra dimensions are smalland compact, extra dimensions in the braneworldapproach can be large and even infinite.

Sahni and Shtanov have studied the cosmo-logical consequences of this approach in which, ourobservable universe is a (3+1)-dimensional ‘brane’which is embedded in a (4+1)-dimensional ‘bulk’space-time. Their work shows that the expan-sion dynamics on the brane can be quite differentfrom that predicted by conventional Einstein grav-ity. The braneworld can accelerate at late times,thus providing one possible explanation for the phe-nomenon of dark energy.

The braneworld cosmology developed by Sahniand Shtanov has several attractive and distinctivefeatures. For instance the effective equation ofstate in braneworld models can be both w0 ≥ −1as well as w0 ≤ −1. This is due to the fact that thebrane can be embedded in the bulk in two comple-mentary ways.

A subclass of braneworld models shows thefascinating property called loitering in which, theHubble parameter dips below its value in ΛCDMat a modest redshift. Loitering models predict alarger age of the universe (at modest redshifts) anda lower redshift of reionization than in ΛCDM. Aremarkable feature of braneworld loitering is that itarises in a spatially flat universe and is sourced bythe projection of five dimensional degrees of free-dom on the brane. Loitering is characterized bythe fact that the Hubble parameter slows down abit over a narrow redshift range referred to as the‘loitering epoch’. During loitering, density pertur-bations are expected to grow rapidly. In addition,since the expansion of the universe slows down, itsage near loitering dramatically increases. An earlyepoch of loitering is expected to boost the forma-tion of high redshift gravitationally bound systemssuch as 109M� black holes at z ∼ 6 and lower-massblack holes and/or population III stars.

Cosmic mimicry

Varun Sahni and Yuri Shtanov have discovered anew possibility within the braneworld paradigm,

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Figure 3: The Hubble parameter for a universe that loiters at zloit � 18. The left panel shows the Hubble parameterwith respect to the LCDM value while, in the right panel, the LCDM (dashed) and loitering (solid) Hubble parametersare shown separately. Three distinct loitering models are shown for illustration.

called Cosmic Mimicry. Cosmic mimicry is char-acterized by the fact that, at low redshifts, theHubble parameter in the braneworld model is vir-tually indistinguishable from that in the LCDM(Λ + Cold Dark Matter) cosmology. An impor-tant point to note is that the Ωm parameter inthe braneworld model and in the LCDM cosmol-ogy can nevertheless be quite different. Thus, athigh redshifts (early times), the braneworld asymp-totically expands like a matter-dominated universewith the value of Ωm inferred from the observa-tions of the local matter density. At low red-shifts (late times), the braneworld model behavesalmost exactly like the LCDM model but with arenormalized value of the cosmological density pa-rameter ΩLCDM

m . The value of ΩLCDMm is smaller

(larger) than Ωm in the braneworld model with pos-itive (negative) brane tension. The redshift whichcharacterizes cosmic mimicry is related to the pa-rameters in the higher-dimensional braneworld La-grangian. Cosmic mimicry is a natural consequenceof the scale-dependence of gravity in braneworldmodels. The change in the value of the cosmo-logical density parameter (from Ωm at high z toΩLCDM

m at low z) is shown to be related to the spa-tial dependence of the effective gravitational con-stant Geff in braneworld theory.

Model independent analysis of an ac-celerating universe

Arman Shafieloo, Ujjaini Alam, Varun Sahni andAlexei A. Starobinsky have developed a new non-parametric method of smoothing supernova dataover redshift using a Gaussian kernel in order toreconstruct important cosmological quantities in-cluding the Hubble parameter and the equationof state of dark energy in a model independentmanner. This method was shown to be success-ful in discriminating between different models ofdark energy when the quality of data is commen-surate with that expected from the future Super-Nova Acceleration Probe (SNAP). Shafieloo, Alam,Sahni and Starobinsky have found that the Hubbleparameter is especially well-determined and usefulfor this purpose. The look back time of the uni-verse may also be determined to a very high degreeof accuracy ( <∼ 0.2%) in this method. By refin-ing the method, it is also possible to obtain rea-sonable bounds on the equation of state of darkenergy. They also explored a new diagnostic ofdark energy the ‘w-probe’, which can be calculatedfrom the first derivative of the data. They foundthat this diagnostic is reconstructed extremely ac-curately for different reconstruction methods evenif Ωm is marginalised over. The w-probe can beused to successfully distinguish between ΛCDM

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Figure 4: An illustration of cosmic mimicry. The Hubble parameter in three low-density brane models with Ωm = 0.04is shown. Also shown is the Hubble parameter in a LCDM model (dotted line) which mimics this braneworld but hasa higher mass density ΩLCDM

m = 0.2. The brane matter-density parameter (Ωm) and the corresponding parameterof the masquerading LCDM model are related in terms of parameters in the higher dimensional Lagrangian. Forthe model shown Ωm <∼ ΩLCDM

m . The redshift interval during which the braneworld masquerades as LCDM, so thatHBRANE2 = HLCDM for z � zm, is zm = 8, 32, 130 (left to right) for the three braneworld models. Note that a lowvalue of Ωm has been shown for illustration. Braneworld models with larger values of Ωm are also straightforward toconstruct.

Fiducial Model: w = −1

Figure 5: The supernova data have been smoothed to obtain H(z) and w(z) from 1000 realizations of the SNAPdataset. The dashed line in each panel represents the fiducial ΛCDM model with w = −1 while the solid linesrepresent the mean and 1σ limits around it. In the left panel H(z) for the fiducial ΛCDM model matches exactlywith the mean value obtained from the smoothing scheme.

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and other models of dark energy to a high degreeof accuracy.

Comprehensive observational con-straints on the evolution of dark en-ergy

The dark energy component of the universe is of-ten modeled in terms of a cosmological constantor a scalar field. A generic feature of the scalarfield models is that the equation of state parame-ter w ≡ P/ρ for the dark energy need not satisfyw = −1 and, in general, it can be a function oftime. Using the Markov chain Monte Carlo methodT. Padmanabhan, in collaboration with H.K.Jassaland J.S.Bagla, has performed a critical analysisof the cosmological parameter space, allowing fora varying w. They use constraints on w(z) fromthe observations of high redshift supernovae (SN-Gold), WMAP observations of CMB anisotropiesand abundance of rich clusters of galaxies. Formodels with a constant w, the ΛCDM model isallowed with a probability of about 6% by theSN-Gold observations, while it is allowed with aprobability of 98.9% by WMAP observations. TheΛCDM model is allowed even within the contextof models with variable w. WMAP observationsallow it with a probability of 99.1%, whereas SNdata allows it with 23% probability. The SN data,on its own, favours phantom like equation of state(w < −1) and high values for ΩNR. The SN-Golddata allows a very wide range for variation of darkenergy density, e.g., a variation by a factor of ten inthe dark energy density between z = 0 and z = 1is allowed at 95% confidence level. WMAP obser-vations provide a better constraint and the corre-sponding allowed variation is less than a factor ofthree.

In short, there is significant tension betweenSN-Gold and WMAP observations; the best fitmodel for one is often ruled out by the other ata very high confidence limit. Given the divergencein models favoured by individual observations, andthe fact that the best fit models are ruled out inthe combined analysis, the authors conclude thatthere is a distinct possibility of the existence of sys-tematic errors in the SN-Gold data which are notunderstood.

This point of view was vindicated more re-cently, when the SNLS (SuperNova Legacy Survey)sample has been released. Applying the same anal-ysis, Jassal, Bagla and Padmanabhan demonstratethat the SNLS results are in better agreement withCMB observations, unlike the SN-Gold data set,which preferred a different class of models alto-gether. The SNLS data set favours models similar

to the ΛCDM model. They illustrate that WMAPobservations are, by far, the strongest constraint onmodels with a varying equation of state parameterfor the dark energy component in a flat universe.Further, the better quality of observations of tem-perature anisotropies in the CMB are less suscep-tible to systematic effects and this makes it a morereliable probe of cosmological parameters and darkenergy. However, given the ease with which the su-pernova observations can be compared with a givencosmological model, theoreticians tend to use onlythe supernova observations for testing models ofdark energy. It is, therefore, useful to know that therecent SNLS data prefers models similar to thosepreferred by WMAP, unlike the previous data setswhich had a certain amount of discordance withWMAP.

Alternative cosmology

Work on the quasi-steady state cosmology is con-tinuing and one of the aspects of the mini-creationevents predicted by this cosmology has been ex-plored further. This concerns the emission ofgravitational waves. In a paper published in theMonthly Notices of the Royal Astronomical Soci-ety, it is shown that the LISA detector will be ableto detect gravitational waves from explosive cre-ation in the form of double radio sources. Theestimated number of events per year will be ap-proximately 1 to 2.

The steady-state theory had used negative en-ergy scalar fields, which have also been subse-quently used for the QSSC. There has been a re-vival of interest in such fields in the form of phan-tom fields. Using the old formalism of the creationfield, work has been going on to see how it affectsthe gravitational collapse of massive objects. J. V.Narlikar has shown that these fields prevent singu-larity and also reverse the collapse before a blackhole is formed.

Cosmic Microwave BackgroundAnisotropy

Cosmic Microwave Background (CMB) anisotropyis a thrust area of astronomy and astrophysics. Thetransition to precision cosmology has been spear-headed by measurements of CMB anisotropy and,more recently, polarization. Besides precise deter-mination of various parameters of the standard cos-mological model, observations have also establishedsome important basic tenets of cosmology andstructure formation in the universe – ‘acausally’correlated initial perturbations, adiabatic nature

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Figure 6: The figure shows likelihoods of w and ΩNR for constant equation of state models. The top panel shows likelihoodswhen we take dark energy perturbations into account and the lower panel is for homogeneous dark energy component. Thesolid/red line is likelihood with WMAP data, blue/dashed line shows SNLS data likelihood and the green dot-dashed line islikelihood plot for gold+silver data.

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primordial density perturbations, gravitational in-stability as the mechanism for structure formation.

The exquisite measurements by the Wilkin-son Microwave Anisotropy Probe (WMAP) re-sults marked a successful decade of exciting CMBanisotropy measurements and considered a mile-stone because they combine high angular resolu-tion with full sky coverage allowed by a space mis-sion. Tarun Souradeep and his collaborators haveworked on a broad range of research problems inCMB anisotropy.

Angular power spectrum of CMBfrom WMAP

Tarun Souradeep, in collaboration with PankajJain and Rajib Saha has carried out an indepen-dent estimation of the angular power spectrumfrom WMAP. This novel, self contained, analysisof multi-frequency data from WMAP evades themodeling uncertainties involved in using extrane-ous foreground model. The angular power spec-trum computed by their analysis matches that fromWMAP. This is also the first demonstration thatthe CMB angular power spectrum can be reliablyestimated with precision from a self contained anal-ysis of the WMAP data, which is a very encourag-ing news for future CMB experiments. Soon af-ter the second release of WMAP data, the Indianteam, in collaboration with five other internationalresearch groups, have carried out comprehensive re-analysis of three years of WMAP data that com-pare the currently important approaches to the es-timation of CMB angular power spectrum.

The independent CMB data analysis pipelinedeveloped in IUCAA allows the study of vari-ous systematic effects that are important for thenext WMAP releases and other future experi-ments. This method is also being viewed with greatpromise for near future CMB polarization measure-ments, like the Planck Surveyor, where very littleis known about the polarized foregrounds.

Effects of non-circular beam onWMAP power spectrum estimate

In this era of high precision CMB measurements,systematic effects are beginning to limit the abilityto extract more information. The non-circularityof the experimental beam has become progres-sively important as CMB experiments strive toattain higher angular resolution and sensitivity.Recent CMB experiments such as ARCHEOPS,MAXIMA, WMAP have significantly non-circularbeams. Future experiments like Planck are ex-pected to be even more seriously affected by non-circular beams. Tarun Souradeep, Sanjit Mitra and

Anand Sengupta, had studied the effect of non-circular beams on CMB power spectrum estima-tion. They showed that a significant correction isexpected for an experiment with a beam which isnon-circular at a level comparable to the WMAPbeam.

Mitra, Sengupta, Subharthi Ray, Rajib Sahaand Souradeep have extended the research work toderive analytic expressions for the effect of non-circular beam for non-uniform sky-coverage. Thissubstantially enhances the results available in theliterature and the analytic expressions could pro-vide a considerable computational advantage indata analysis pipelines.

Statistical anisotropy of the CMBmaps from WMAP

The statistical expectation values of the tempera-ture fluctuations of cosmic microwave background(CMB) are assumed to be preserved under rota-tions of the sky. The assumption of statisticalisotropy (SI) of the CMB anisotropy should be ob-servationally verified since detection of violation ofSI could have profound implications for cosmology.The Bipolar Power Spectrum (BiPS) has been re-cently proposed as a measure of violation of statis-tical isotropy in the CMB anisotropy map by AmirHajian and Tarun Souradeep. This has been de-scribed in detail in the last year’s annual report.

The first ‘full’ sky CMB polarization mapshave been recently released in the WMAP-3yr sec-ond data release. The statistical isotropy of theCMB polarization maps is an independent probeof the cosmological principle. Since CMB polariza-tion is generated on the surface of last scattering,violations of statistical isotropy are pristine cosmicsignatures and difficult to explain as local effectsin the universe. In the first study of SI violationin CMB polarization maps, Soumen Basak, Ha-jian, Souradeep have extended the Bipolar PowerSpectrum for CMB polarization maps and demon-strated its use in identifying SI violation in CMBpolarization maps.

Besides implementing BiPS on data, somework has been done by Hajian and Souradeep onthe physical effects probed by the BiPS. In collab-oration with Pogosyan, Bond and Contaldi, theyhave computed the BiPS predicted for non-trivialcosmic topology. Himan Mukhopadhyay, Hajianand Souradeep have also worked on the idea ofa Bipolar power spectroscopy of cosmic topologybased on the interesting, observable, connection be-tween the symmetries of the compact universe mod-els and the measurable BiPS of CMB anisotropy.Tuhin Ghosh, Hajian and Souradeep have usedthe BiPS power spectrum to constrain anisotropic

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Figure 7: The angular power spectrum estimated from the WMAP multi-frequency using a self-contained model free approachto foreground removal (black curve) is compared to the WMAP team estimate (red) [Saha, Jain and Souradeep, ApJ. Lett.2006]. The method does not rely upon any foreground templates and exploits only basic physical facts such as the achromaticCMB fluctuations and the lack of noise correlation between the independent channels. The published binned WMAP powerspectrum plotted in red line with error bars for comparison. The lower panel shows the difference in the estimated powerspectra. The method holds great promise for CMB polarization, where modeling uncertainties for foregrounds are much higher.

models of cosmology. Saha, Hajian, Jain andSouradeep have also shown that the BiPS is an ex-cellent diagnostic to check for residual foregroundsin CMB maps.

Constraining early universe scenariosfrom observations

Cosmological parameters estimated from CMBanisotropy (and related observations) assume a spe-cific form for the spectrum of primordial pertur-bations believed to have seeded the large scalestructure in the universe. Accurate measurementsof the angular power spectrum Cl over a widerange of multipoles from the Wilkinson MicrowaveAnisotropy Probe (WMAP) has opened up the pos-sibility to deconvolve the primordial power spec-trum for a given set of cosmological parameters.Arman Shafieloo and Tarun Souradeep have devel-oped and implemented a direct deconvolution ap-proach to estimate the primordial power spectrumfrom the angular power spectrum CMB anisotropymeasured by WMAP that has cited in the re-cent second release of WMAP data. Shafielooand Souradeep are undertaking a fresh analy-sis based on the angular power spectra of theCMB anisotropy and polarization. Rita Sinha andSouradeep have assessed promising inflationary sce-

narios that incorporate similar infra-red cutoff un-dertaking a comprehensive cosmological parameterestimation exercise. Yashar Akrami, and TarunSouradeep developed a numerical code for rapidlycomputing the predicted spectrum of perturbationsfor a given inflation potential. This will allow jointestimation of the parameters of inflation poten-tial and cosmological parameters from the availablecosmological data on CMB anisotropy and large-scale galaxy surveys.

Observational Cosmology

Discovery of an immense ring-likestructure of radio emission aroundgalaxy cluster Abell 3376

The origin of ultra-high energy cosmic ray parti-cles (UHECR) with surprisingly large energies of∼ 1018 − 1020 eV is a long-standing enigma ofPhysics. In any acceleration scheme, the radia-tion background induced energy losses and sourcesize/energy constraints put a limit to the attain-able maximum energy. Observationally, cosmic raysources of required parameters are yet unidentified.Some potential UHECR accelerator sources are ra-dio galaxies (lobes, jets), pulsar magnetospheres,

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Figure 8: Top panel: A composite map of radio and X-ray emission from the galaxy cluster Abell 3376. The radio emissionis represented by yellow contours (0.12, 0.24, 0.48 and 1 mJy/beam. Beam width: 20 arcsec FWHM Gaussian) obtained fromthe VLA 1.4 GHz observations. The yellow ellipse shows an elliptical fit to the peripheral radio structures and the ‘+’ marksthe center of the fitted ellipse. The central colour image depicts the thermal bremsstrahlung X-ray emission structure detectedby the PSPC detector onboard the ROSAT satellite in ≈12 ks exposure and within 0.14–2.0 keV band. The red circles markthe position of the two brightest cluster galaxies - the brightest cD galaxy on the lower-right and the second brightest galaxyassociated with the bent-jet radio source MRC 0600-399 near the X-ray peak. Bottom panel: Composite maps obtained fromradio and optical images. The VLA 1.4 GHz radio maps (in red colour) for the eastern (left) and the western (right) shockstructures are shown overlayed on the red band Digitized Sky Survey image (in yellow-green colour).

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Figure 9: (a) XMM-Newton MOS1 and MOS2 composite photon image in the [0.3-8.0] keV band. The black circle showsthe position of the second brightest galaxy, which coincides with the X-ray peak. (b) Red band Digitized Sky Survey imagewith ROSAT [0.2-2.0] keV smoothed intensity iso-contours superposed. The brightest cluster galaxy (BCG) is indicated withan arrow. The BCG sits at the edge of the ROSAT field of view but outside of the XMM field of view. (c) Temperature map(color scale in keV units) derived from XMM data. Notice the alternating cold and hot regions, their temperature varying from∼ 2 to ∼ 6 keV. The superposed X-ray intensity contours are from an adaptively smoothed XMM image. (d) Metallicity map(color scale in solar units) derived from XMM data. It shows a strong metallicity gradient along the intensity elongation axis.Contours are the same as in the previous panel. The scale bars are in kpc, assuming z = 0.046 and standard ΛCDM cosmology.

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gamma-ray bursts, and galaxy clusters. Clusters ofgalaxies are the largest known virialised structures,which assemble by gravitational infall of smallermass components. Accretion, mergers and colli-sions are the dominant processes of ‘structure for-mation’. In these processes, an important role isplayed by megaparsec scale cosmic shock waves,arising in gravity-driven supersonic flows of inter-galactic matter (IGM) onto dark matter dominatedcollapsing structures such as pancakes, filamentsand clusters of galaxies. During cluster mergers,the enormous kinetic energy of colliding subclus-ters (∼ 1063−64 erg) is dissipated in the form ofshock-waves, which play a pivotal role in heating ofthe intra-cluster medium (ICM) to the virial tem-peratures. Large scale structure-formation shocksin the presence of magnetic fields are capable of ac-celerating particles upto ultra-relativistic limit by adiffusive shock acceleration process (DSA or Fermi-I), although many details of this process are stillhazy due to lack of good observational data.

To understand better what role shock waves inclusters might play as cosmic-ray particle acceler-ators, J. Bagchi and collaborators (Florence Dur-ret, Gastao Lima Neto and Surajit Paul)have madethe massive cluster of galaxies Abell 3376 the focusof their study. In Abell 3376, they found severalevidences of ongoing energetic structure-formationprocesses - subcluster mergers, large-scale periph-eral shocks etc. They targeted Abell 3376 withdeep VLA and GMRT observations at 1.4 GHz fer-quency. They have discovered a unique, large-scale(∼ 2 Mpc) ring-like synchrotron radio emissionstructure, possibly tracing the elusive intergalac-tic shocks around this galaxy cluster at redshift z= 0.046. This immense ring-like structure [Fig-ure 8] contains mainly a pair of giant, arc shapeddiffuse radio emitting sources, each with a lineardimension ∼ 1h−1 Mpc, located at the outskirtsof this cluster at the projected distance of ∼ 1h−1

Mpc from the cluster centre. In addition, the east-ern structure contains several linear filaments anda peculiar loop like feature. The immense physicalsize of these radio structures places them amongthe largest shock wave features ever seen.

Both radio structures were found to be ori-ented such that their concave side faces the clustercenter and they fitted quite well on the surface ofa large, projected elliptical ring-like formation ofdimension ∼ 2 × 1.6 Mpc2 in position angle ≈ 85◦

[Figure 8]. The luminous thermal bremsstrahlungX-ray emission detected by the ROSAT satelliteand onboard PSPC detector is also shown in Fig-ure 8. In the cluster central region, it revealsa highly disturbed, non-equilibrium state of theintra-cluster thermal gas, which is obviously ex-tended like a ‘comet’ or ‘bullet-head’, its wake

running parallel to the major axis of the radiostructures described above. Both radio sources arelocated at the periphery of the ROSAT-observedX-ray emission. From redshift measurements ofgalaxies in this cluster, a filamentary structurecomposed of at least three major subclusters, ori-ented parallel to the ellipse major axis, is reported.Obviously, Abell 3376 is far from being a relaxedcluster.

The X-ray temperature, metal abundance andintensity maps derived from XMM-Newton dataare displayed in Fig. 9. Typical errors on tem-peratures on this map are about 10%. This mapreveals an overall temperature of about 5 keV, withseveral alternating hot and cold regions crossingthe cluster, divided by a prominent ‘cold-arc’ atabout 3 keV, which originates at the north edgeand curves southwards towards the east. The mostplausible scenario is that a large group or a smallcluster is falling onto the main body of the clusterfrom the east-northeast, thus creating hotter re-gions through a shock. Such a scenario would agreewith the second brightest galaxy on the X-ray peakassociated with the strong radio source MRC 0600-399, in which both radio-jets are bent backwardssuggesting a movement towards the west-southwestalong PA∼ 70◦ (Fig.8). It also agrees with the factthat this cannot be a relaxed cluster, since the twobrightest galaxies are not at all close to the clustercenter, as defined by the X-ray distribution (Fig.89). The highly asymmetrical metal distributionalso suggests a violent and recent dynamical event,where the gas is not well mixed and we observepatches of high and low metallicity. All these ev-idences indicate hydrodynamically unrelaxedd na-ture of Abell 3376.

Due to relatively short radiative timescale ofrelativistic electrons, particle transport by diffusionfrom an AGN like point source upto ∼ Mpc dimen-sion will not work and they must be accelerated insitu. The lack of any identifiable galaxy progen-itor or radio jets/plumes connecting the periph-eral radio sources with any central AGN/opticalgalaxy suggests that these structures can not bethe diffuse radio lobes. Hydrodynamical simula-tions show that only shock waves induced in struc-ture formation processes are sufficiently extended,long-lived, and energetic to overcome the strongradiation losses of the relativistic electrons over aMpc-scale, rapidly accelerating them to relativisticenergies, which could emit synchrotron radio emis-sion at the level observed. These ubiquitous shocksare an inevitable consequence of gravitational col-lapse and they are pivotal to virialization of diffuseinter-galactic medium (IGM). Two such shockwaveinducing events are plausible: the supersonic accre-tion flows of IGM and their associated virial shocks,

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and the merger shocks emanating from the cen-tre induced by merger events of subclusters ∼ 109

yr in the past (assuming constant shock speed of∼ 1000 km/s). A pair of outgoing merger shockwaves could have created these diffuse radio sourcesat the outskirts of Abell 3376 by accelerating a pre-existing lower energy electron population. Alterna-tively, their peripheral ring-like geometry at ∼ Mpcdistance from centre inidicates that these giant ra-dio structures could be the first direct evidence forthe accretion shocks near the yet unexplored virialinfall region of a massive galaxy cluster, and thusa direct probe of dynamics of warm-hot intergalac-tic gas (so called WHIM). More work is continuedto decide which of the three processes is actuallyobserved here.

The gas dynamics induced in structure forma-tion (large-scale bulk flows, turbulence, collision-less shocks and modified magnetic fields) all cre-ate an ideal environment for cosmic ray acceler-ation via stochastic Fermi-I mechanism, and foramplification of seed magnetic fields. For cosmicray protons, which suffer negligible radiative lossesbelow 5 × 1018 eV, the highest acceleration en-ergy EP

max is limited only by the finite lifetimeof shocks, i.e., tacc = tmerger ∼ 109−10 y, thusgiving EP

max ∼ 1018−19 eV. For cosmic ray elec-trons significant radiative losses limit their energyto a maximum Ee

max ∼ 1014 eV. Lower energyelectrons of ∼ 10 GeV energy would produce theobserved 1.4 GHz radio emission. Inverse Comp-ton scatter of the 2.7 K cosmic microwave back-ground photons from both primary electrons ac-celerated in shocks, and from secondary electronsof hadronic origin (from pion decay and pair pro-duction), will give rise to energetic hard X-ray/γ-ray photons of energy Eγ ∼ 100 γe

72 GeV (where

γe7 is the electron Lorentz factor in units of 107).

The Inverse Compton spectrum could extend upto∼ 10 TeV, limited by higher energy cut-off in theelectron energy spectrum. This tell-tale radiationremains undetected, but future identification ofhard X-ray (ASTRO-E2, NEXT) or 1 MeV - 100GeV (GLAST) to VHE TeV γ-ray (CANGAROO,MAGIC, VERITAS, HESS) emission from struc-ture formation shocks in hydrodynamically unre-laxed clusters like Abell 3376 holds a great promisefor advancing current knowledge on shock forma-tion in the IGM. It should provide the first directevidence for such shocks, revealing the underlyinglarge-scale cosmological flows and definitive proofof ultra-high-energy cosmic ray acceleration. Whencombined with hard X-ray or γ-ray detection, theradio synchrotron signal (GMRT, SKA, LOFAR)will probe directly the unknown magnetic fields inthe IGM, thus providing a better understanding ofprocesses leading to IGM magnetization and also

acceleration and propagation of ultra-high energycosmic rays.

Magnetic Fields in Astro-physics

Magnetic helicity density and its fluxin weakly inhomogeneous turbulence

Magnetic helicity conservation plays a crucial rolein constraining the nonlinear evolution of severalastrophysical and laboratory plasma systems. It isimportant for practical applications involving sys-tems with boundaries, to be able to discuss thedensity of magnetic helicity and its flux. This isdifficult when one defines the magnetic helicity us-ing the vector potential, because then the magnetichelicity density or its flux are not gauge invariantconcepts.

K. Subramanian and A. Brandenburg haveproposed a gauge invariant and hence physicallymeaningful definition of magnetic helicity densityfor random fields, using the Gauss linking formula,as the density of correlated field line linkages. Thisdefinition was applied to the random small scalefield in weakly inhomogeneous turbulence, whosecorrelation length is small compared with the scaleon which the turbulence varies. For inhomogeneoussystems, with or without boundaries, our techniquethen allows one to discuss the local magnetic helic-ity density evolution, in a gauge independent fash-ion, which was not possible earlier. This evolutionequation is governed by local sources (owing to themean field) and by the divergence of a magnetichelicity flux density. Such magnetic helicity fluxescan help in alleviating catastrophic quenching ofmean field dynamos. Their work, to some extent,lays the conceptual foundation for the many discus-sions of the effects of helicity fluxes already existingin the literature and future explorations.

Strong mean field dynamos requiresupercritical helicity fluxes

K. Subramanian and A. Brandenberg have also be-gun the exploration of the effects of such a helic-ity flux in solving the catastrophic quenching ofdynamos. Several one and two dimensional meanfield dynamo models were analyzed, where the ef-fects of helicity fluxes and boundaries are included.Even in the absence of helicity fluxes, the field canreach appreciable strength at the end of a kinematicphase. This is as anticipated in their earlier work,where they had worked out the minimal strength oflarge-scale magnetic fields, which can be generated,in spite of strict magnetic helicity conservation.

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However, due to helicity conservation and non-linear effects, the field undergoes oscillations, witha fast decay and slow rise, when for long periods,the field can be extremely weak, with its amplitudeinversely proportional to the magnetic Reynoldsnumber. Since the magnetic Reynolds number istypically very large in astrophysical systems, thiswould be disastrous for mean field dynamo theory.

The inclusion of helicity fluxes alters these con-clusions. If the helicity flux exceeds a certain criti-cal value then one can circumvent the catastrophicquenching of the dynamo, and the field can satu-rate at appreciable values. Infact, for supercriticalhelicity fluxes, the dynamo can operate even with-out kinetic helicity, i.e., it is based only on shearand helicity fluxes, as first suggested by Vishniacand Cho. The fact that certain turbulence simu-lations have now shown apparently non-resistivelylimited mean field saturation amplitudes may besuggestive of the helicity flux having exceeded thiscritical value.

Galactic dynamo and helicity lossesthrough fountain flow

For the galactic dynamo, simple advection as ex-pected in the galactic fountain flow can lead tothe necessary helicity flux. K. Subramanian, A.Shukurov, D. Sokoloff, and A. Brandenburg haverecently studied the nonlinear behaviour of galac-tic dynamos, allowing for magnetic helicity removalby the galactic fountain flow. A suitable advectionspeed is estimated, and an one-dimensional mean-field dynamo model with dynamic α-effect has beenexplored. The galactic fountain flow is indeed ef-ficient in removing magnetic helicity from galacticdiscs, and alleviate the constraint on the galacticmean-field dynamo due to magnetic helicity con-servation. The mean magnetic field then saturatesat a strength comparable to equipartition with theturbulent kinetic energy

Active Galactic Nuclei,Quasars and Intergalactic

Medium

Properties of high redshift quasars

In the local universe, the masses of Super-MassiveBlackholes (SMBH) appear to correlate with thephysical properties of their hosts, including themass of the dark matter halo. Using these cluesas a starting point, many studies have producedmodels that can explain phenomena like the quasarluminosity function. The shortcoming of this ap-

proach is that working models are not unique, andas a result, it is not always clear what input physicsis being constrained. Following up on the work re-ported last year, Stuart Wrythe and T. Padmanab-han have analysed some aspects of this issue usinga different approach. They identify critical param-eters that describe the evolution of SMBHs at highredshift, and constrain the parameter space basedon observations of high redshift quasars from theSloan Digital Sky Survey. They find that the lu-minosity function taken in isolation is somewhatlimited in its ability to constrain SMBH evolu-tion due to some strong degeneracies. This ex-plains the presence in the literature of a range ofequally successful models based on different physi-cal hypotheses. Including the constraint of the lo-cal SMBH to halo mass ratio breaks some of thedegeneracies and their results suggest halo massesat z ∼ 4.5 of 1012.5±0.3M� (with 90% confidence),with a SMBH to halo mass ratio that decreaseswith time (> 99%). These features need to be in-corporated in all successful models of SMBH evolu-tion. Current data does not permit any conclusionsregarding the evolution of quasar life time, or theSMBH occupation fraction in dark matter halos.

Molecular hydrogen in a dampedLyman-alpha system at zabs=4.224

Molecular hydrogen (H2) is the first neutralmolecule to be formed in the universe and is an im-portant coolant for the first generation of stars. Inthe local universe, H2 is ubiquitous in star-forminggiant molecular clouds, diffuse interstellar medium(ISM) and in the atmospheres of Jovian planets. Inthe diffuse ISM, H2 molecules are mainly formed onthe grain surface and destroyed by the UV photonswith typical energy ∼10 eV (called Lyman-Wernerband photons). Thus, equilibrium abundance andthe population of H2 in different rotational levelstogether with excitation of fine-structure states C0

are used to get a handle on physical conditions suchas gas pressure, ambient radiation field and chem-ical history, etc. These conditions are believed tobe driven by the injection of energy and momentumthrough various dynamical and radiative processesassociated with the star formation activity. Thus,detecting H2 molecule at high z is an importantstep to understand the evolution of normal galax-ies.

R. Srianand and his collaborators CedricLedoux and Patrick Petitjean, have reported the di-rect detection of molecular hydrogen at the highestredshift known today (zabs = 4.224) in a DampedLyman-alpha (DLA) system toward the quasar PSSJ1443+2724 (see Fig. 10). This absorber is re-markable for having one of the highest metallicities

32

Figure 10: Velocity profiles of selected transition lines from the J = 0, 1, 2, 3 and 4 rotational levels of the vibrationalground-state Lyman and Werner bands of H2 at zabs = 4.224 toward PSS J 1443+2724. The best Voigt-profile fitting model issuperimposed on the spectra with vertical dotted lines marking the location of the three components of the system.

amongst DLA systems at zabs>3, with a measurediron abundance relative to Solar of −1.12 ± 0.10.They provide for the first time in this systemaccurate measurements of N i, Mg ii, S ii andAr i column densities. The sulphur and nitro-gen abundances relative to solar, −0.63± 0.10 and−1.38±0.10 respectively, correspond exactly to theprimary nitrogen production plateau. H2 absorp-tion lines are detected in four different rotationallevels (J = 0, 1, 2 and 3) of the vibrational ground-state in three velocity components with total col-umn densities of log N(H2)=17.67, 17.97, 17.48and 17.26 respectively. The J=4 level is tenta-tively detected in the strongest component with logN(H2)= 14. The mean molecular fraction is log f =−2.38 ± 0.13, with f = 2N(H2)/(2N(H2)+N(H i)).They also measure log N(HD)/N(H2)< −4.2. Theexcitation temperatures T01 for the two main com-ponents of the system are 96 and 136 K respec-tively. They argue that the absorbing galaxy,whose star-formation activity must have started atleast 2−5×108 yrs before z=4.224, is in a quiescentstate at the time of observation. The density of thegas is small, nH ≤ 50cm−3, and the temperatureis of the order of T = 90-180 K. The high exci-tation of neutral carbon in one of the componentscan be explained if the temperature of the CosmicMicrowave Background Radiation has the expectedvalue at the absorber redshift, T=14.2 K.

Relative abundance pattern alongthe profile of high redshift DampedLyman-alpha systems

Understanding the chemical and ionization inho-mogeneities in DLAs is important for our under-standing of production and mixing of metals in nor-mal galaxies. R. Srianand and his collaborators E.Rodriguez, P. Petitjean, B. Aracil and C. Ledouxhave investigated the abundance ratios along theprofiles of six high-redshift Damped Lyman-alphasystems, three of them associated with H

2

absorp-tion, and derived optical depths in each velocitypixel. The variations of the pixel abundance ra-tios were found to be remarkably small and usu-ally smaller than a factor of two within a profile.This result holds even when considering indepen-dent sub-clumps in the same system. The depletionfactor is significantly enhanced only in those com-ponents, where H

2

is detected. They found a strongcorrelation between [Fe/S] and [Si/S] abundancesratios, showing that the abundance ratio patternsare definitely related to the presence of dust. Thedepletion pattern is usually close to the one seenin the warm halo gas of our Galaxy. Some of thecomponents that produce H2 absorption have de-pletion pattern close to that seen in the cold neutralmedium of our galaxy.

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Kinematics and star formation activ-ity in the z=2.03954 damped Lyman-α system towards PKS 0458-020

Multiwavelength investigations of DLAs allow usto probe the physical conditions in protogalax-ies in detail. Recently R. Srianand and his col-laborators have conducted UVES observations ofthe log N(HI) = 21.7 damped Lyman-α systemat z = 2.03954 towards the quasar PKS 0458-020.They have detected a H i Lyman-alpha emissionin the centre of the damped Lyman-alpha absorp-tion trough. Metallicities are derived for MgII, SiII,PII, CrII, MnII, FeII and ZnII and are found to be−1.21±0.12,−1.28±0.20,−1.54±0.11,−1.66±0.10,−2.05 ± 0.11, −1.87 ± 0.11, and −1.22 ± 0.10, re-spectively, relative to solar. The depletion factoris, therefore, of the order of [Zn/Fe]=0.65. Theyobserve metal absorption lines to be blueshiftedcompared to the Lyman-alpha emission up to amaximum of 100 and 200 km/s for low and high-ionization species respectively. This can be inter-preted either as the consequence of rotation in alarge (∼7 kpc) disk or as the imprint of a galacticwind. The star formation rate (SFR) derived fromthe Lyman-alpha emission, 1.6 solar masses/yr, iscompared with that estimated from the observedCII* absorption. No molecular hydrogen is de-tected in our data, yielding a molecular fractionf < −6.52. This absence of H2 can be explained asthe consequence of a high ambient UV flux, whichis one order of magnitude larger than the radiationfield in the ISM of our Galaxy and originates inthe observed emitting region. This work was donein collaboration with Janine Heinmueller, PatrickPetitjean, Cedric Ledoux and Sara Caucci.

On the variation of the fine-structureconstant: Very high resolution spec-trum of QSO HE 0515-4414

As part of continued effort to measure/constrainthe possible time variations of fundamental con-stants Hum Chand and R. Srianand with their col-laborators have recently presented a detailed anal-ysis of a very high resolution (R ≈112,000) spec-trum of the quasar HE 0515−4414 obtained usingthe High Accuracy Radial velocity Planet Searcher(HARPS) mounted on the ESO 3.6 m telescopeat the La Silla observatory. This is the high-est resolution spectra ever obtained for the highredshift QSOs. The HARPS spectrum, of veryhigh wavelength calibration accuracy (better than1mA ), is used to search for possible systematicinaccuracies in the wavelength calibration of theUV Echelle Spectrograph (UVES) mounted on theESO Very Large Telescope (VLT). They have car-

ried out cross-correlation analysis between the Th-Ar lamp spectra obtained with HARPS and UVES.The shift between the two spectra has a dispersionaround zero of σ 1mA . This is well withinthe wavelength calibration accuracy of UVES (i.e.,σ 4mA ). They show that the uncertaintiesin the wavelength calibration induce an error ofabout, Δα/α ≤ 10−6, in the determination of thevariation of the fine-structure constant. Thus, theresults of non-evolving Δα/α reported in the litera-ture based on UVES/VLT data should not be heav-ily influenced by problems related to wavelengthcalibration uncertainties. Their higher resolutionspectrum of the zabs=1.1508 damped Lyman-α sys-tem toward HE 0515-4414 reveals more compo-nents compared to the UVES spectrum. Usingthe Voigt profile decomposition that simultane-ously fits the high resolution HARPS data and thehigher signal-to-noise ratio UVES data, they ob-tain, Δα/α = (0.05± 0.24)× 10−5 at zabs=1.1508.This result is consistent with the earlier measure-ment for this system using the UVES spectrumalone. This work was done in collaboration withPatrick Petitjean, Bastien Aracil, Ralf Quast andDieter Reimers.

A new constraint on the time depen-dence of the proton-to-electron massratio.

A new limit on the possible cosmological variationof the proton-to-electron mass ratio μ = mp/me

is estimated by measuring wavelengths of H2 linesof Lyman and Werner bands from two absorp-tion systems at zabs= 2.5947 and zabs= 3.0249 inthe spectra of quasars Q 0405-443 and Q 0347-383, respectively. Data are of the highest spec-tral resolution (R = 53000) and S/N ratio (30÷70)for this kind of study. R. Srianand, Hum Chandand their collaborators search for any correlationbetween zi, the redshift of observed lines, deter-mined using laboratory wavelengths as references,and Ki, the sensitivity coefficient of the lines toa change of μ, that could be interpreted as avariation of μ over the corresponding cosmologicaltime. They have used two sets of laboratory wave-lengths, the first one, (Set A), based on experimen-tal determination of energy levels and the secondone, (Set P), based on new laboratory measure-ments of some individual rest-wavelengths. Theyfind Δμ/μ = (3.05 + −0.75)10−5 for Set A, andΔμ/μ = (1.65 + −0.74)10−5 for Set P. The sec-ond determination is the most stringent limit onthe variation of μ over the last 12 Gyrs ever ob-tained. The correlation found using Set A seemsto show that some amount of systematic error is

34

hidden in the determination of energy levels of theH2 molecule. This work was done in collaborationwith A. Ivanchik, P. Petitjean, D. Varshalovich, B.Aracil, C. Ledoux and P. Boisse.

Galaxies

Galaxy formation and evolution

Many clues to galaxy formation lay hidden in thefine details of galaxy structure. Active galacticnuclei (AGNs) are intimately related to formationof bulges and black holes. A key question in as-trophysics is the nature of the AGN host galax-ies. The Great Observatories Origins Deep Sur-vey (GOODS) provides a homogenous sample ofdeep, multiwavelength observations of galaxies us-ing data from Hubble, Spitzer Space Telescope,Chandra and XMM-Newton. This provides a veryunique database of AGNs, starburst galaxies andnormal galaxies in wavelengths ranging from in-frared to X-ray. The GOODS database can be usedto understand the morphology, spectral proper-ties and evolution process of peculiar objects (withsome indication of AGN activity) in this sampleusing indicators like their Xray luminosity, radioflux, etc. P. Hasan, A. K. Kembhavi, A. Rawat,F. Hammer and H. Flores have studied the crosscorrelatation of X-ray source catalogues and theHST/ACS z850 catalogues of the GOODS field ob-tained with Chandra deep field survey with cat-alogues in the optical. Refined techniques havebeen used to identify most probable counterparts.Morphological classification is essential to revealthe nature of AGN host galaxies. However, athigh redshifts, it becomes difficult to classify galaxymorphology securely, because the images of highredshift galaxies suffer from reduced resolution,band shifting and cosmological surface brightnessdimming effects, compared with the local objects.With HST ACS, high resolution imaging in two ormore bands with spatially resolved colour distri-bution can be used to investigate the distributionof the stellar population, which is complementaryto single band images. For further reference, theyhave also carried out decomposition of the luminos-ity profiles of the galaxies using GALFIT, to derivethe bulge to disk ratios and possible features inresidual maps. The figure 11 shows an example ofa galaxy with its corresponding colour map whichclearly shows star forming regions, dusty regions,etc.

High Energy Astrophysics

One of the most enigmatic sources in the universeare black hole systems. Over several decades, acomprehensive understanding of these sources, es-pecially their temporal behaviour, has remained il-lusive, because of the complexities involved in solv-ing the governing magneto-hydrodynamic equa-tions. R. Misra, K. P. Harikrishnan, G. Ambikaand A. K. Kembhavi have developed a modifiedversion of a standard non-linear time series analy-sis and have applied the technique on light curvesof black hole systems. They find that some sys-tems exhibit low dimensional chaotic behaviour,which implies that the partial differential equationswhich govern the system, can be simplified into aset of non-linear but ordinary differential ones. Al-though, their analysis does not reveal the exact na-ture of these equations, their results indicate thatthe temporal behaviour of such systems can indeedbe understood in a simple framework.

Identification of the radiative processes thatoccur in black hole systems, is crucial to the un-derstanding of these systems. S. Bhattacharyya,N. Bhatt and R. Misra have improved on their ear-lier results, to work out the possibility that some ofthe high energy emission of X-ray binaries is due toproton-proton interactions. Such a scenario is moreattractive, since it is difficult to accelerate electronsin such environments.

Ultra-luminous X-ray (ULX) sources are X-ray points sources in nearby galaxies, which areextremely bright (> 1039 ergs/sec) and hence, areexpected to harbour intermediary size black holes(102 − 104M�). A. Senorita, R. Misra, V. K.Agrawal and Y. P. Singh have undertaken a system-atic spectral study of these sources. V. K. Agrawaland Misra have analyzed the spectra of the ULXM822 X-1, and have found it to be different fromother low luminosity black hole sources, indicatingthat it is perhaps emitting on the Eddington limit.

Stars and Interstellar Medium

A multiwavelength investigation ofthe temperature of the cold neutralmedium

Physical state of the local interstellar median canbe probed either using 21 cm (H i) absorption orusing the rotational distribution of H2. Recently R.Srianand and his collaborators Nirupam Roy andJayaram Chengalur have presented GMRT mea-surements of the H I spin temperatures (Ts) ofthe Cold Neutral Medium (CNM) towards radiosources that are closely aligned with stars for which

35

-4-2

02

4

-4 -2 0 2 4

0 1 2 3 4

Figure 11: z (F850LP) band image and colourmap made using the B (F435W) and z (F850LP) band filters for a z = 0.27interacting galaxy.

Figure 12: Fitting of interstellar polarization values (in square dots) with the composite grain model polarization.

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4500 5000 5500 6000 6500 70000

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1 CB62-1 ANN O7I

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Figure 13: Spectral classification by ANN technique of the peripheral stars around the dark star forming cloudCB62.

published H2 ortho-para temperatures (T01) areavailable from UV observations. Their sample con-sists of 18 radio sources close to 16 nearby stars.The transverse separation of the lines of sight ofthe UV and radio observations varies from 0.1 to12.0 pc at the distance of the star. The ultravi-olet (UV) measurements do not have velocity in-formation, so they use the velocities of low ioniza-tion species (e.g., Na I, K I, C I) observed towardsthese same stars to make a plausible identificationof the CNM corresponding to the H2 absorption.They find that T01 and Ts match within observa-tional uncertainties for lines-of-sight with H2 col-umn density above 1015.8 cm−2, but deviate fromeach other below this threshold. This is consistentwith the expectation that in the CNM, Ts tracksthe kinetic temperature due to collisions and thatT01 is driven towards the kinetic temperature byproton exchange reactions.

Physical conditions in the ISM to-wards HD185418

R. Srianand and his collaborators, Gary Ferlandand Gargi Shaw, have developed a complete modelof the hydrogen molecule as part of the spectralsimulation code Cloudy. Their goal is to applythis to spectra of high-redshift star-forming regions,

where H2 absorption is seen, but where few otherdetails are known, to understand its implication forstar formation. The microphysics of H2 is intricate,and it is important to validate these numerical sim-ulations in better-understood environments. As afirst step they studied a well-defined line-of-sightthrough the galactic interstellar medium (ISM) asa test of the microphysics and methods they use.They have presented a self-consistent calculationof the observed absorption-line spectrum to de-rive the physical conditions in the ISM towardsHD185418, a line-of-sight with many observables.They deduce density, temperature, local radiationfield, cosmic ray ionization rate, chemical composi-tion and compare these conclusions with conditionsdeduced from analytical calculations. They find ahigher density, similar abundances, and require acosmic ray flux enhanced over the galactic back-ground value, consistent with enhancements pre-dicted by MHD simulations.

Modeling of interstellar dust

R. Gupta in collaboration with D.B. Vaidya andT.P. Snow have used the composite dust grainmodel to reproduce the interstellar polarizationand also given better abundance contraints for car-bon and silicon in the ISM. Figure 12 shows the

37

composite model polarization and its fitting withSerkowiski’s points (square dots).

Spectrophotometric observations ofdark clouds

R. Gupta and Asoke K. Sen have carried out spec-troscopic observations from Hanle telescope of theperipheral stars in the dark star forming cloudshave been reduced and the Figure 13 shows a typi-cal ANN based spectral classification of the spectraof such stars around the cloud CB62. These resultsalong with the B and V band photometry will pro-vide the estimate of colour excess and extinction,which will in turn provide the information whetherthese stars are in the foreground or at the back-ground of the cloud.

PCA based scheme for filling the gapsin stellar spectral libraries

Recently alongwith H.P. Singh, M. Yuasa and N.Yamamoto, R. Gupta has made a preliminary at-tempt to fill the gaps in the stellar spectral librariesby using the PCA technique. This technique willbe used to restore the gaps in all available digitalspectral libraries in near future.

Instrumentation

NIPI - Near-Infrared PICNIC Imager

A. Deep,A. N. Ramaprakash and others in the in-strumentation laboratory are working on buildinga near-IR camera to be mounted on one of theCassegrain side ports of the IUCAA Girawali tele-scope. NIPI will be the first near-IR instrumentto be used on this telescope, providing wavelengthcoverage over 1-2.5 microns with a spatial samplingscale of about 0.8 arcseconds per pixel.

NIPI has a hybrid cryostat, made up of twoseparate parts - a standard dewar with liquid ni-trogen tank, purchased from Infrared Labs, USAand an extension, which houses the lenses, mirrors,filter wheel and the detector. The dewar extensionis made using a special aluminium alloy, ingots ofwhich were imported from Germany. By the timethe ingots were delivered last year, the design of allthe mechanical mounts and support structures werecompleted. The dewar extension and the mountsfor optical components were machined and fabri-cated with the help of local industry. A radiationshield for providing thermal insulation for the op-tical components inside the dewar extension wasalso fabricated and assembled. Currently, tests are

being carried out to achieve liquid nitrogen tem-peratures on the cold block, on which the detectorwill be mounted. The required temperatures are tobe reached by providing thermal paths to the de-war cold face as well as adequate shielding againstradiative heat load. On the other hand, damage tothe detector by rapid cooling must be avoided byproviding adequate thermal mass to the cold block.

The entire assembly consisting of the IR Labssupplied liquid nitrogen dewar as well as the dewarextension were tested for vacuum and cryogenic in-tegrity in the laboratory. An operating vacuumof 10−5 mbar was achieved prior to cooling andfew times 10−6 mbars after cooling. The assembledchamber was found to hold the vacuum very well formore than 20 days during laboratory tests. A fea-ture worthy of special mention about the cryogenicsystem is that the laboratory developed a vacuumfeed through which allows the filter wheel mecha-nism inside the extension chamber to be rotated us-ing an ordinary stepper motor mounted outside thechamber. This eliminates the need for alternativeoptions like using expensive and fragile cryogenicmotors inside the chamber.

The mounts for the lenses and mirrors werecoated with Nextel infrared black paint to mini-mize scattering from their surfaces. The opticalcomponents were then carefully mounted on theirholders and the holders on the optical bench. Thethree mirrors which define the optic axis were firstalinged using an HeNe laser source and appropri-ate masks. The lenses were then aligned on theoptic axis using the same laser source and employ-ing retro-reflection techniques. In this technique, iflight reflected from each surface in the optical pathcome back to the source, the surfaces are along theoptical axis. Once the optics were satisfactorilyaligned, the bench was mounted inside the dewarextension chamber and the radiation shield assem-bled around it. The last component to go in is thefilter wheel on its stainless steel shaft. The instru-ment is currently in its final phase of assembly inthe laboratory and is planned to be mounted onthe telescope very soon.

Instrument control system

The back-end instruments on the telescope are op-erated during observations from the control roomin the ground floor of the observatory. Although,there are a lot of similarities between the require-ments for control of different instruments and ac-cessories, currently many of these have been im-plemented differently, due to historic developmentcycles. A project was undertaken last year to de-velop a unified control system, which will meet thecurrent and immediate future instrument control

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Figure 14: Spectra of IRAF spectroscopic standard star HR4963 taken with the IUCAA Girawali telescope andIFOSC instrument (IFOSC 7 grism) and its fitting with IRAF narrow band fluxes.

requirements at the observatory. In addition to of-fering a unified command-reponse-recovery inter-face, this system will also have substantial redun-dancy in the hardware to meet contingencies. Thesystem is also extendable to meet future increasein demands. It also provides a LAN-based com-mand interface in addition to the traditional se-rial communication link based ones. The hardwareis built around the Atmel make Atmega 128 mi-crocontroller and is designed with a back-plane ar-chitecture with configurable plug-play sub-systems.Industry standards have been adopted in the designof the printed circuit cards as well as the enclosurebox. M. Srivastava, and A. N. Ramaprakash havebeen working with instrumentation laboratory staffon this project.

Observatory science verification

With the hand over of the 2m telescope from Tele-scope Technologies Ltd, UK, to IUCAA in Febru-ary 2006, service mode observations were startedat the observatory as reported elsewhere in this re-port. A. N. Ramaprakash played a vital role inthe activities related to converting the telescopefrom an engineering product to a working obser-vatory. He was also actively involved in traininga core group of observers from IUCAA in the op-erational and observational usage of the observa-tory. Apart from carrying out science verificationstudies, particularly with the polarimetric mode ofIFOSC, Ramaprakash along with M. Srivastavahas initiated a spectroscopic campaign of ultralu-minous infrared galaxies.

IUCAA Girawali telescope andIFOSC spectral characterization

During the current phase of the characterization ofIUCAA Girawali telescope along with the IFOSCinstrument, observations were made for IRAF stan-dard stars and Figure 14 shows a fitting of one suchspectra from HR4963 with the IRAF narrow bandfluxes.

Cryosampler balloon experi-ment

The cryosampler equipment was flown up from theTIFR Balloon Facility, Hyderabad, to a height of 41km using a balloon. The cryopump was used suc-cessfully to collect samples of air at varying heightsupto 41 km. The payload was brought down safelyand the samples were sent to the Centre for Cel-lular and Molecular Biology in Hyderabad and tothe National Centre for Cell Science in Pune. S.Shivaji in Hyderabad and Yogesh Shouche in Puneare currently examining the samples to detect mi-croorganisms. Final findings in this experiment areexpected to be reported within the next six monthsand J. V. Narlikar is involved in this experiment.

39

(II) RESEARCH BY VIS-ITING ASSOCIATES AND

LONG TERM VISITORS

Gravitational Theory and

Gravitational Waves

Banerjee, S. K.

Bhim Prasad Sarmah, in collaboration with S.K.Banerjee, S.V. Dhurandhar and J.V. Narlikar hasconsidered the cosmogony of the creation processthat leads to the creation and ejection of matter.They show why the creation phenomenon mayhave a non-isotropic character, with ejection tak-ing place along preferred directions. To measureits gravitational-wave effect they calculate thegravitational amplitude generated by an MCE(mini -creation event) of mass M at a cosmologicaldistance r, and then compare the signal-to-noiseratio detectable by the ground-based laser inter-ferometric detectors of the LIGO and the advanceLIGO type within the frequency range 10 to 1000Hz with the signal-to-noise ratio detectable bythe Laser interferometric Space Antenna (LISA)within the frequency range 10-4 to 10-1 Hz.

The calculations they performed here showthat a laser interferometric detector of the LISAtype can be used to detect through a window oflow-frequency range 10-4 Hz to 2 x 10-2 Hz for aduration of about 52 min. In this duration, LISAwill be able to see ’jets’ for which, the mass cre-ation rate is at least 200 solar mass per second.Whereas, a laser interferometric detector of the ad-vance LIGO type can be used to detect the MCEs,which opens its window of high-frequency range 10to 103 Hz for a very short duration of the order of10-2 seconds, and in this duration it observes ’jets’for which, the mass creation rate is 2 x 104 solarmass per second. It appears from this elementaryanalysis that the LISA detector is well suited todetecting MCEs through their gravitational waves,while the LIGO may have a less sensitive, marginalrole to play.

Chakraborthy, Subenoy

Quasi-spherical gravitational collapse both in fourand higher dimensional spacetime has been stud-ied by Subenoy Chakraborty and co-workers. S.Chakraborty and U. Debnath have examined therole of anisotropy and inhomogeneity in quasi-spherical gravitational collapse in the form ofpropositions. They have investigated the role of ini-tial data in characterizing the final state of collapse.Also, they have presented a linear transformationon the initial data set and discussed its impact in

the collapsing process. A dynamical symmetry ofthe quasi-spherical (or spherical) collapse has beenstudied by S. Chakraborty in collaboration with U.Debnath and Naresh Dadhich. By linear scalingthe initial data set (mass and kinetic energy func-tions), they have shown that the dynamics of quasi-spherical (or spherical) collapse remains invariantfor dust or a general (Type-I) matter field, withappropriate scaling of the comoving radius. Theyhave found an equivalence class of data sets, whichleads to the same end result as well as its evolutionall through the physical parameters, namely, den-sity and shear, remain invariant. The role of pres-sure in quasi-spherical gravitational collapse hasbeen studied by S. Chakraborty in collaborationwith Sanjukta Chakraborty and U. Debnath. Cos-mological solutions and their asymptotic behaviourhave been examined by them for perfect fluid andmatter with tangential stress only. They have pre-sented collapsing scenario for anisotropic pressureand have discussed the role of pressure.

Ibohal, Ng

A class of rotating solutions of Einstein’sfield equations including Kerr-Newman-Vaidya,Kerr-Newman-Vaidya-de Sitter, Kerr-Newman-monopole describing embedded black holes, havebeen derived by Ng Ibohal. The physical proper-ties of these solutions observing the nature of en-ergy momentum tensors and Weyl scalars describ-ing gravitational field have been discussed. He haspresented the surface gravity, entropy and angu-lar velocity for each of these embedded black holesas they are important parameters. He has studiedthe Hawking’s radiation and has presented variousclassical spacetime metrics affected by the changein the masses, describing the possible life style ofradiating embedded black holes in different stagesduring evaporation process.

In another paper he has proposed a rotatingnon-stationary de Sitter solution of Einstein’s fieldequations with a variable cosmological term. Itis found that the spacetime of the rotating non-stationary de Sitter model is an algebraically spe-cial in the Petrov classification of gravitational fieldwith a null vector, which is geodesic, shear free, ex-panding as well as non-zero twist. However, space-time of non-rotating non-stationary model is con-formally flat with non-empty space. This work hasbeen done with L. Dorendro.

Jotania, Kanti and Ramesh Tikekar

The conventional approach of obtaining relativisticmodels of super-dense stars in equilibrium whichrequires a priori information of the equation ofstate (EOS) for its fluid content for solving the as-

40

sociated Einstein field equations (EFE) is not ap-plicable for compact objects such as neutron stars,strange stars (SS), hybrid neutron stars etc. Suchstars have matter with densities exceeding nuclearmatter densities and no reliable information aboutEOS available. The interest in promoting under-standing of such compact objects in the relativis-tic set up warrants the search for alternative ap-proaches. With this motivation, Ramesh Tikekarand Kanti Jotania have been examining the suit-ability of Vaidya-Tikekar (VT) ansatz and ansatzsimilar to that, prescribing suitable geometry forthe three space of the interior spacetime of a com-pact star. The geometrical parameters associatedwith the models obtained in this way have beenfound linked with mass, mass to size ratio, the den-sity variation and the central matter densities ofthe configurations. This approach suggests thatthe geometric considerations would provide deeperinsight for the spacetime structure of compact starsand the EOS of their matter content. The studyof gravitational collapse of spherical distribution ofmatter with such compact objects has the final out-come and the collapse of such object to black holeswhen their equilibrium is lost, will be topic of in-teresting investigations.

Tikekar and Jotania have studied the modelsof compact stars like SAX (J1808.4-3658), Her. X-1 etc. obtained by using an ansatz, similar to thatof VT, prescribing pseudo-spheroidal geometry fortheir interior spacetimes. The physical viability ofthe models of this class has been investigated bythem using numerical procedures and the EOS ofthe fluid content of the models studied has beenfound to admit linear forms under suitable approx-imate procedures.

Finch and Skea had obtained a two parameterclass of relativistic models of relativistic stars, crit-ically examined their physical relevance and dis-cussed their suitability for neutron star interpre-tation. Tikekar and Jotania observed that the 3-space of the interior spacetimes of Finch-Skea mod-els have the geometry of a 3-paraboloid immersedin 4-dimensional Euclidean space and found thatit is possible to choose the two parameters of thisfamily of solutions as the central density of mat-ter and the compactification parameter (mass tosize ratio), constituting two physical observablescharacterizing the models. Their study indicatesthat the class of models based on the paraboloidalansatz include models representing configurationsless massive and smaller in size compared to neu-tron stars and admitting higher values for compact-ification factor than those of neutron stars.

It is apparent that the alternative approachis potent to provide criteria to characterizestrange matter state, nuclear-density with self-

bound hadronic matter at high densities : de-confined quark matter state or di-quark matterstate or exotic strange matter state.

Nandi, K. K.

Kamal Kanti Nandi, along with collaborators, hasbeen engaged in studying various aspects of clas-sical and quantum gravity including Brans-Dicketheory. They have shown that the conformal in-variance of the vacuum Brans-Dicke action can beused as a tool to rule out many newly proposed so-lutions. Scalar field contribution to entropy in thebackground of static and rotating black hole met-rics has been studied using the brick wall method.A rather curious example, mainly of pedagogicalinterest, has also been worked out in which, theyhave shown how some general relativity equationscan be obtained from the Newtonian theory itself.

Patil, K. D.

Vaidya solution represents null dust fluid and hasbeen extensively used to study the formation ofnaked singularities in spherically symmetric grav-itational collapse. Husain solution can be consid-ered as a generalization of Vaidya solution and hasbeen used as the formation of black hole with shorthair. K. D. Patil and U. S. Thool have investigatedthe nature of the singularities arising in the grav-itational collapse of Husain spacetime and shownthat under certain condition on the mass function,strong curvature naked singularities do form in thiscollapse. What will be the final outcome of the col-lapse, which is not spherically symmetric? Mustnon-spherical collapse produce a black hole? Unlikethe spherical symmetric case, very little is knownabout the cosmic censorship in non-spherical col-lapse. Patil and Thool have shown that the non-spherical gravitational collapse of asymptoticallyanti-de-Sitter Husain solution leads to the forma-tion of a naked singularity, while the collapse ina cosmological solution proceeds to form a blackhole.

Ray, Saibal

Einstein-Maxwell field equations corresponding tohigher dimensional description of static sphericallysymmetric spacetimes have been solved by SaibalRay in collaboration with Sumana Bhadra and G.Mohanty. Electromagnetic mass models are provedto exist in higher dimensional theory of general rel-ativity corresponding to charged dust distribution.Along with the general proof, a specific example isalso sited as a supporting candidate.

41

Saibal Ray, in continuation of (n + 2) dimen-sional spacetimes, studied the above problem un-der two specific set of conditions, viz., (i) ρ �= 0,ν′ = 0, and (ii) ρ = 0, ν′ �= 0, where ρ and νrepresent the mass density and metric potential.The solution sets thus obtained, satisfy the crite-ria of being electromagnetic mass model such thatthe gravitational mass vanishes for the vanishingcharge density σ and also the spacetime becomesflat. Physical features related to other parametersalso have been discussed.

Einstein-Maxwell spacetime also has been con-sidered by Saibal Ray in collaboration with BasantiDas, Subharthi Ray and Farook Rahaman in con-nection to some of the astrophysical solutions aspreviously obtained by Tolman (1939) and Bayin(1979). The effect of charge inclusion in these solu-tions has been investigated thoroughly and also thenature of fluid pressure and mass density through-out the sphere have been discussed. Mass-radiusand mass-charge relations have been found out forvarious cases of the charged matter distribution.Two cases are obtained where, perfect fluid withpositive pressures give rise to electromagnetic massmodels. The stability conditions have been in-vestigated for all these Tolman-Bayin type staticcharged perfect fluid solutions in connection to thestellar configurations.

Srivastava, D. C.

D.C. Srivastava is investigating the various meth-ods of getting exact solutions for Plane SymmetricStatic Perfect Fluids (PSSPF). The motivation ofthis work is the remark made in this context byStephani et al. in their recent book.

“Using (15.51), many static solutions could beobtained from the vast number of known sphericallysymmetric solutions given in § 16.1, but so far thismethod has not been exploited.”

The key point is the equation (15.51),

2GL,xx = LG,xx

x ={

r2, k = 1r, k = 0

where k is the curvature of orbit S2; its value 1 rep-resents the spherical symmetry and zero the planesymmetry. This equation represents the pressureisotopy condition. The metric of the space-time isgroup theoretical approach may be expressed col-lectively as

ds2 = L−2(r)[R2(r){(dx1)2 +

2∑(x1, k)(dx2)2} + dr2 − G2(r)dt2

];(1)

∑(x1, k) = (Sinx1, x1) for k = 1, 0, respectively.

This equation has been obtained for spherical sym-metry by Kustaanheimo and Quist as early as 1948and needs to be studied in depth. The exact so-lutions for SSSPF distributions have been studiedfor more than four decades. Recently, a couple ofreview articles relating to them have appeared inliterature where, the symmetries of the equationsto be solved are exploited to provide the generaltechniques and the classification scheme.

Classical and Quantum Cos-

mology

Banerjee, Narayan

Narayan Banerjee has studied various possibilitiesfor explaining the present acceleration of the uni-verse. He has investigated scalar field cosmologieswith a trigonometric potential, a complex scalarfield and also a scalar field with a possible trans-fer of energy with matter. He has also studied therole of curvature in driving the acceleration of theuniverse.

Chakraborty, Subenoy

Cosmological solutions in the background ofRandall-Sundrum brane-world-type-scenario havebeen evaluated by S. Chakraborty, B. C. Santraand N. Chakravarty. They have studied theBianchi V spacetime model in the background ofa 5D bulk having non-vanishing Weyl tensor witha viscous fluid as matter content and have investi-gated the physical properties of these solutions.

Chandra, Deepak

Deepak Chandra has continued his study on thedark energy problem in cosmology. It is believedthat the scalar field models play an important rolein describing the current observations, which in-dicate that our universe is accelerating due to thepresence of a matter component with negative pres-sure like the cosmological constant. Deepak Chan-dra has been exploring the different dark energymodels and their equations of state. Also, he hasbeen investigating the cosmological evolution of dif-ferent fields and potentials like scalar fields, phan-tom fields, Chaplagyn gases, etc. and exploringtheir impact on the future evolution of our uni-verse.

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Debnath, U.

U. Debnath, in collaboration with S. Bhanja andS. Chakraborthy has considered a decaying cosmo-logical constant, and particle production in an adi-abatic process have been considered as the sourcesfor the entropy for anisotropic model of the uni-verse with constant energy per particle. The modelwith non-flat universe and can describe the evolu-tion of the universe from radiation era to ΛCDMmodel, but beyond radiation in the past is not de-scribable by the model - probably some quantumtheory is necessary to describe the evolution of theearly era.

It is well known that when a fermion propa-gates in curved spacetime, its spin couples to thecurvature of background spacetime. This interac-tion for neutrinos propagating in early curved uni-verse could give rise to a new set of dispersion rela-tions and then neutrino asymmetry at equilibrium.They demonstrate this with the Bianchi models,which describe the homogeneous but anisotropicand axially symmetric universe. If the lepton num-ber violating processes freeze out at 10-37 secondwhen temperature GeV, neutrino asymmetry ofthe order of 10-10 can be generated. A net baryonasymmetry of the same magnitude can, thus, begenerated from this lepton asymmetry either bya GUT B - L symmetry or by the electro-weaksphaleron processes, which have B + L symmetry.

Jain, Deepak

Over the last years, a considerable number of high-quality observational data have transformed rad-ically the field of cosmology. Results from dis-tance measurements Type Ia supernovae combinedwith CMB observations and with dynamical esti-mates of the quantity of matter in the universesuggest that the universe is spatially flat and un-dergoing a phase of acceleration. An energy com-ponent with negative pressure, widely referred asdark energy, was invoked to explain the apparentacceleration of the universe. However, it is alsowell known that effects arising from new physicscan mimic the gravitational effects of dark energythrough modification of the Friedmann equation.Deepak Jain along with Abha Dev, and Jailson S.Alcaniz have investigated the observational conse-quences of a flat matter dominated and accelerat-ing/decelerating scenario, in which this modifica-tion is given by H2 = g(ρm, n, q). The g(ρm, n, q) isa new function of energy density ρm, the so calledCardassian models. They mainly focus attentionon the constraints from the CLASS lensing sampleon the parameters n and q that fully characterizethe models.

They also considered the possibility of discrim-inating between the various evolving dark energymodels and ΛCDM models using the joint analysisof CLASS statistical sample and Sne gold sample.

Deepak Jain and Abha Dev have also discussedthe observational constraints on various parameter-izations of dark energy from age measurements ofold high redshift objects.

Assuming general time dependence of the scalefactor, R ∝ tα , Deepak Jain, Abha Dev and G.Sethi have investigated observational constraintson the dimensionless parameter, α. The model isconsistent with the latest Sne Ia “gold” sample andaccommodates a very high old high-redshift quasar,which the standard cold-dark matter model fails todo.

John, Moncy V.

Using an improved version of the model-independent, cosmographic approach, Moncy V.John has addressed an important question relevantto cosmology: Was there a decelerating past forthe universe? To answer this, the Bayes’s proba-bility theory was employed, which is the most ap-propriate tool for quantifying our knowledge whenit changes through the acquisition of new data. Thecosmographic approach helps to sort out the mod-els, in which the universe was always acceleratingfrom those in which it decelerated for at least sometime in the period of interest. Bayesian model com-parison technique is used to discriminate these rivalhypotheses with the aid of recent releases of super-nova data. It was also attempted to provide andimprove another example of Bayesian model com-parison, performed between some Friedmann mod-els, using the same data. The conclusion, which isconsistent with the earlier results, is that the ap-parent magnitude-redshift data alone cannot dis-criminate these competing hypotheses.

Pandey, Sanjay K.

It is widely accepted that the large scale struc-tures (of the universe) originated from initiallysmall density fluctuations were a Gaussian randomfield. Non-Gaussian features arise as the fluctu-ation growth through the process of gravitationalinstability. Quantifying these at the various stagesof the growth is expected to yield a significantamount of information. The three-point correlationfunction and its Fourier transform, and the bispec-trum, are the lowest order statistics sensitive tonon-Gaussian features. Sanjay Pandey, in collabo-ration with S. K. Saiyad Ali and Somnath Bharad-waj, has investigated the possibility of using thefluctuations in the redshifted 21 cm radiation from

43

the neutral hydrogen (HI) to detect the bispectrumarising from nonlinear gravitational clustering andfrom nonlinear bias. They have calculated the ex-pected signal for GMRT and have found that themagnitude of the signals from the bispectrum iscomparable to that from the power-spectrum, al-lowing a detection of both in roughly the same in-tegration time. They have also considered the pos-sibility of using observations of the bispectrum todetermine the linear and quadratic bias parametersof the HI at high redshifts, this having possible im-plications for the theories of the galaxy formation.

Paul, B. C.

B. C. Paul has studied the evolution of a flatFriedmann- Robertson-Walker universe in a higherderivative theory in the presence of a variable cos-mological constant considering a varying Newton’sgravitational constant. He obtains new cosmologi-cal solutions, which are important for model build-ing. A cosmological model is permitted in whichgravitational constant varies initially, which, how-ever, attains a constant value at a later epoch.

Following Bousso and Hawking, the probabil-ity for quantum creation of a universe with a pairof primordial black holes (PBH) in a modified the-ory of gravity with higher order terms in additionto an inverse power of scalar curvature (dR − 1)introduced by Carroll, et al. has been evaluated byB. C. Paul. He obtains a class of instanton solu-tions, which permit quantum creation of an infla-tionary universe. He notes that the probability ofa pair of primordial black holes suppressed with apositive cosmological constant when 0 < d < L2.It is also found that unlike Bousso and Hawking,de Sitter instantons without PBH and with PBHare permitted even in the absence of a cosmologicalconstant (L) in the modified gravity.

Pradhan, A.

A. Pradhan, together with G. S. Khadekar and M.R. Molaei has studied the multi dimensional cos-mological implications of a decay law for cosmo-logical term Λ. It is widely believed that a con-sistent unification of all fundamental forces in na-ture is possible within the spacetime with an extradimension beyond those four observed so far. Theabsence of any signature of extra dimensions in cur-rent experiments is usually explained for compact-ness of extra dimensions. It has been observed thatsuch models are compatible with the results of ob-servations, and cosmological term Λ gradually re-duces as the universe expands. Kaluza-Klein typeR-W cosmological models with dynamical cosmo-logical term Λ(t) have been studied by A. Pradhan,

Saeed Otarod and co-authors. The proper distance,the luminosity distance-redshift, the angular diam-eter distance-redshift, and look back time-redshiftfor the models are presented in the frame work ofhigher dimensional spacetime.

Models with dynamic cosmological term Λ(t)becoming popular as they solve the cosmologicalconstant problem in a natural way. Generation ofBianchi type V cosmological models with varyingcosmological term Λ are studied by A. Pradhan,together with A. K. Yadav and L. Yadav. Theyhave also studied spatially flat bulk viscous LRSBianchi type I cosmological models with a time de-pendent displacement field within the frame workof Lyra’s geometry. These type of studies may berelevant for inflationary models. A. Pradhan, G.P. Singh and co-authors have studied causal bulkviscous LRS Bianchi type I models with variablegravitational and cosmological “constant”.

The occurrence of magnetic fields on galacticscale is a well-established fact today and their im-portance for a variety of astrophysical phenomenais generally acknowledged. E. R. Horrison has sug-gested that magnetic field could have a cosmologi-cal origin. As a natural consequences, we shall in-clude magnetic fields in the energy momentum ten-sor of the early universe. Anisotropic magnetic fieldmodels have significant contribution in the evolu-tion of galaxies and stellar objects. In this context,a detailed study of relevant theories has been un-dertaken by A. Pradhan, Purnima Pandey and K.K. Rai by considering plane-symmetric and Bianchitype I metric.

Ray, Saibal

Saibal Ray and Utpal Mukhopadhyay are continu-ing the investigations on dynamical models of thecosmological term Λ in connection to the dark en-ergy theory.

Choosing a phenomenological model of Λ, viz.,Λ ∼ H, it has been shown by Ray and Mukhopad-hyay that this model of Λ is equivalent to otherthree types of Λ, Λ ∼ (a/a)2, Λ ∼ a/a, and Λ ∼ ρ.Through an indirect approach, it has also been pos-sible to put a limit on the deceleration parameterq. It has been shown that if q becomes less than−1, then this model can predict about the presenceof phantom energy.

Two phenomenological models of Λ, viz., Λ ∼(a/a)2 and Λ ∼ a/a are also studied by them underthe assumption that G is a time-variable parame-ter. Both models show that G is inversely pro-portional to time as suggested earlier by others,including Dirac. The models considered here canbe matched with observational results by properlytuning the parameters of the models. Our anal-

44

ysis shows that Λ ∼ a/a model corresponds to arepulsive situation and hence, correlates with thepresent status of the accelerating universe. Theother model Λ ∼ (a/a)2 is, in general, attractive innature. Moreover, it is seen that due to the com-bined effect of time-variable Λ and G the Universeevolved with acceleration as well as deceleration.This later one indicates a Big Crunch.

Seshadri, T. R

T. R. Seshadri has studied a model of scalar-tensortheory of gravitation, in which the scalar field, φ de-termines the gravitational coupling G and has a La-grangian of the form, Lφ = −V (φ)

√1 − ∂μφ∂μφ.

This work has been done in collaboration with SanilUnnikrishnan. It has been shown that there is atransition from an initial decelerated expansion (inthe matter dominated era) to an accelerated ex-pansion phase at the present epoch. Using obser-vational constraints, it has been shown that theeffective equation of state today for the scalar fieldturns out to be pφ = wφρφ, with wφ = −0.88 andthat the transition to an accelerated phase hap-penned at a redshift of about 0.3.

Singh, G. P.

Exact solutions of general theory of relativity forspatially homogeneous spacetimes belongs eitherto the Bianchi types or to Kantowski-Sachs space-times. The isotropic Friedmann-Robertson-Walker(FRW) models are special cases in the Bianchi clas-sification. The Bianchi models can be coupled toany gravitational theory. A number of authors haveinvestigated the nature of cosmological solutionsfor homogeneous Bianchi type models. As dissi-pative effects, including bulk and shear viscositiesplay a very important role in expansion of the uni-verse, cosmological models with dissipative processhave been extensively investigated in an attemptsto explain the formation and evolution of the earlyuniverse. Recent observations provide us an evi-dence that the expansion of the universe is acceler-ating at the present epoch. This apparent acceler-ation is attributed to dark energy residing in space.The literature suggests that dark energy representapproximately 70 % of the total energy density ofthe universe. The most straightforward source ofdark energy is a cosmological constant, but a levelof fine tuning necessary to make it a variable can-didate is disconcerting. To explain this dark en-ergy, another alternative Q-matter or quintessencehas been introduced. This energy propose a scalarfield that slowly rolls down it’s potential with thekey property of having a negative pressure. G. P.Singh and his coworkers have studied some Bianchi

type I cosmological models with bulk viscous cos-mic fluid in the presence of quintessence, cosmolog-ical and gravitational constants.

Due to the possibility of the large extra-dimensions in the brane-world models, the cosmo-logical models of the early universe must be stud-ied with careful consideration of the effect of thehigher dimensional geometry. It has been suggestedthat brane-world models satisfy both recently re-leased Supernova data sets: the Gold data and thedata from the Supernova Legacy Survey (SNLS).A number of authors have studied multi dimen-sional cosmological models in different context. G.P. Singh and his collaborators have presented a newclass of higher dimensional cosmological models .The new models obtained in these investigationsgenerate several known models and results are wellwithin the range of observational limits.

Galaxies and Quasars

Jog, Chanda

N-body simulations of mergers of spiral galaxieswith an emphasis on the case of unequal-massgalaxies, covering the mass ratios 1:1- 10:1 was car-ried out by C. J. Jog. The study uses a powerfulFFT code and a million particles per galaxy andincludes the effects of gas, thus, the study treatsrealistic galaxies. It is shown that the mass ratios1:1-3:1 give rise to elliptical-like remnants, whilethe ratios 4.5:1-10:1 result in peculiar, mixed sys-tems with spiral-like mass profiles and elliptical-like kinematics. The transition between these twocases occurs over a surprisingly narrow range ofmass ratios- this is important in understanding thedynamical evolution of elliptical galaxies (see Bour-naud, Jog, and Combes 2005 for details).

Near-IR data for a large sample of 149 galax-ies from the OSU catalogue have been Fourier-analyzed to obtain the lopsided density distributionand the potential in the disks. A large fraction (30%) of these galaxies show significant lopsidedness.N-body simulations were carried out to identify thephysical mechanism for its origin. These show thatgalaxy interactions can generate high amplitudeof lopsidedness, however in addition asymmetricgas accretion onto a galaxy is required to explainall the statistical results observed, see (Bournaud,Combes, Jog and Puerari 2005) for details.

Warps are a common feature of spiral galax-ies, and a large fraction of these are now known tobe asymmetric. C. J. Jog and K. Saha propose andwork out the mechanism for the origin of the asym-metric warps as arising due to a dynamic superpo-sition of m = 1 modes (s-shaped warps) and m =

45

0 modes (bowl-shaped distribution). The results,naturally, explain the wide variety of asymmetry inwarps that is observed, including the extreme casesof U-shaped and L-shaped warps, see Saha and Jog(2006) for details.

Khare, Pushpa

Pushpa Khare along with her collaborators stud-ied a large sample of strong Mg II absorbers inthe spectra of QSOs, from the Data Release 1 ofthe Sloan Digital Sky Survey. They constructedabsorber rest frame composite spectra of varioussub-samples of their sample of 809 QSOs, to de-termine the average abundances and average dustextinction in the QSO absorbers. Their study pro-duced definite evidence for the presence of dust inthe intervening absorbers; QSOs with absorbers intheir spectra are at least three times more likely tobe highly reddened as compared to QSOs withoutany absorbers in their spectra. No evidence wasfound for the 2175. A bump in the average extinc-tion curves. The abundances in the absorbers werefound to decrease with increasing reddening in thesub-samples. Close to solar abundance was foundin the sub-sample of 698 absorbers with average HI column density of 1020 cm -2.

She along with her collaborators observed sev-eral low redshift Damped Lyman Alpha systems(DLAs) in the spectra of QSOs, with the VeryLarge Telescope and an equal number of DLAs withthe Magellan telescope (both in Chili) with the aimof determining the metal abundances in these sys-tems.

Pandey, S. K.

As a part of ongoing programme on multiwave-length surface photometric studies of early-typegalaxies in collaboration with A. K. Kembhaviand others, deep CCD images of several early-typegalaxies were obtained in BVRI broad bands andH-alpha using the 2m Himalaya Chandra Telescope(HCT) of IIA during 2005-06. Preliminary reduc-tion of the data has been completed, and detailedanalysis of properties of dust in the sample galaxiesis in progress. Samridhi Kulkarni, a research stu-dent at Raipur, is also involved in this programme.Huge amount of data from a variety of sky sur-veys are available for further investigation. It isplanned to make use of multiwavelength data ongalaxies from LFC fields as apart of the collabo-ration. The LFC survey has been done using theLarge Format Camera on 200-inch Hale telescopeat Mount Palomar Observatory. The field diameterof detector is 25 arcmin with pixel scale of 0.36perpixel after rebinning. Twelve fields, each of area

0.25 square degree is observed to cover 3 squaredegree area of the sky. The data of LFC survey isnot public, but it has been made available to thegroup at IUCAA by one of the original observers,namely, Ashish Mahabal to make use of the datafor further detailed study on galaxies in individualframes. Preliminary study of LFC fields shows thatall the images of these fields have excellent signalto noise ratio. It is possible to reach up to 0.3% ofthe sky level to study the fainter parts of the galaxyand still have significant signal-to-noise ratio. Themulti-wavelength study of statistically significantsample of detected objects from this survey canaddress wide variety of issues in Astronomy andAstrophysics, including galaxy formation and evo-lution, AGN structure and demographics, etc. Af-ter preliminary data reduction, Sextractor(softwarefor source extraction) has been used for the detec-tion, classification of sources and final preparationof the catalogue of galaxies. Detailed analysis ofindividual galaxies from the catalogue of galaxies,thus, made is in progress. Laxmikant Chaware, aresearch student at Raipur, is involved in this pro-gramme.

Pandey, U. S.

U. S Pandey has worked on properties of self-gravitating gaseous disks which are presumed tobe the precursor of massive dark objects (MDOs)as the energy source at the centres of active galac-tic nuclei (AGNs) and quasars. They obtain mass-density ρ and surface mass-density σ in terms ofparticular solution of a linear differential equationof third order. Gravitational potential W androtational velocity Vc profiles are also obtained.They have calculated and plotted the variation ofρ, σ, W and Vc with distance from the centre. Theyhave discussed the perturbation of self-gravitatinggaseous disk to test their stability. An instabilitycriterion has been derived for a stratified plane diskwith uniform σ and Ω. This is found in agreementwith Toomre instability criterion under short waveradial gravitational perturbation. For a typicalJeans disk, they have shown that critical Toomrewavelength is larger than the radius of the disk im-plying unstable radial perturbation for practicallyall wavelengths. Surface mass-densities are shownto be crucial to the evolution of gaseous disks. Theyhave established inter-relationship between variousσ. It is shown that degeneracy near the mid-plane,turbulent velocity and surface temperature are ef-fective parameters to determine the nuclear burn-ing phase of the disk.

46

Patil, M. K.

Recent imaging surveys using ground-based as wellas space telescopes across the electromagnetic spec-trum have amply demonstrated that early-typegalaxies, ellipticals (E) and lenticulars (S0), har-bour multi-phase ISM. In particular, deep CCDimaging and their careful analysis have revealedthat a large fraction (∼ 80%) of E-S0 populationcontain dust features in a variety of morphologicalforms. Study of physical properties of dust in ex-tragalactic environment provides useful clues, notonly for understanding origin and fate of the dust inexternal galaxies but also for the subsequent evolu-tion of the host galaxies. M. K. Patil, along with S.K. Pandey, A. K. Kembhavi, U. C. Joshi, and D. K.Sahu, has carried out multicolour (optical as wellas near-IR) surface photometric analysis of a largesample of early-type galaxies with an objective ofstudying dust extinction properties in extragalac-tic environment. Extinction curves derived for thesample galaxies run parallel to the galactic extinc-tion curve implying that properties of dust in ex-tragalactic environment are quite similar to thoseof the Milky Way, and are characterized by a pa-rameter Rv, ratio of total extinction in V band tothe selective extinction in B and V bands. How-ever, the Rv values are found to be function of thedust morphology as well as environment of the hostgalaxy, in the sense that galaxies with well defineddust morphologies exhibit smaller Rv values. Dustmasses derived from optical extinction are foundto be an order of magnitude smaller than those de-rived from the IRAS flux densities, indicating thata significant fraction of dust intermixed with starsremains undetected by the optical method. As re-gard to the issues of origin of dust in early-typegalaxies, they have determined the injection rateof dust into the ISM by mass-losing evolved starsand have observed that the dust mass quantifiedthrough optical extinction exceeds the total dustaccumulated by a galaxy over its lifetime. Thisin turn implies that at least a part of dust havebeen acquired by the galaxies through a merger likeevent. They are also involved in studying morpho-logical and spectral properties of the hot gas heatedto temperatures ∼ 106 - 107 K in the early-typegalaxies selected from different environments. Thisinvolves analysis of the high resolution X-ray im-ages from Chandra and XMM-Newton space mis-sions. From this analysis, they have derived diffuseemission maps and spectra of the hot gas alone,excluding resolved point sources. Fits to the sur-face brightness profiles and spectra yielded in de-termination of the surface density, length scale andtemperature of the hot gas. This study has alsoresulted in to the detection of a number of point

sources in the E/S0 galaxies, majority of which areLMXBs with X-ray luminosities spanning a widerange from 10 37 erg/s to over 10 39 erg/s.

Compact Objects and X-ray Bi-

naries

Ambika, G.

In collaboration with R Misra, A K Kembhavi andK. P. Harikrishnan, the various types of long termvariability exhibited by the blackhole system GRS1915+105, have been explained by G. Ambika interms of deterministic nonlinear behaviour in thepresence of inherent stochasticity. The results ofthe study indicate that the equations governing themagneto-hydrodynamic flow of the inner accretiondisk can be approximated by a small number ofnonlinear differential equations.

Chattopadhyay, Tanuka

Tanuka Chattopadhyay, in collaboration with Ra-jeev Misra and Asis Kumar Chattopadhyay has ap-plied a new clustering technique to the BATSE cur-rent GRB catalogue data to obtain the optimumnumber of coherent groups of GRB and have foundthree classes as found by Balastegui, et al. (2001)and Mukherjee, et al. (1998). The longest durationclass has mean duration 63.1 sec and intermediateduration class has mean duration 15.85 sec, whichis longer than found by Mukherjee, et al. (1998).The longest duration class is most inhomogeneouswith < V/V max >∼ 0.15, being the deepest pop-ulation with zmax ∼ 10. They have also carriedout discriminant analysis to verify the level of effi-ciency of the above clustering and the value of theproportion constant (at 95% confidence) is found tobe 0.954. They have used the HETE2 GRB withknown red shifts and have carried out clustering ofthe BATSE data with respect to two parameterslogT90 and logFt into three classes and calculatedthe probabilities of HETE 2 GRB’s with knownred shifts in falling these three classes and tried tocalculate their luminosities and original distances.They are developing a Dirichlet Process of MixtureModelling for a second way of classification of theGRB’s of BATSE data to verify whether the ”threeclass classification” is compatible with the presentclassification scheme.

Dey, Jishnu and Mira Dey

In the past, the Equation of State (EOS) wasderived for strange quark matter using the phe-nomenological Richardson potential which con-

47

tained one single scale parameter for asymptoticfreedom (AF) and confinement. It is important touse different AF and confinement scales and withthese baryon masses and magnetic moments arerechecked. With self consistent Debye screeninglength a refined EOS is derived at different temper-atures and the Mass - Radius of the compact objectcalculated. Density dependent quark masses leadto decoupling of fpi.

The compact stars showing broad absorptionband and the gravitational red shift lines arestrange star candidates. We have noted that inone star both are simultaneously observed.

Surface tension in a body is due to the in-ward force experienced by particles at the surfaceand usually gravitation does not play an importantrole in this force. But in compact stars the grav-itational force on the particles is very large andthe surface tension is found to depend not only onthe interactions in the strange quark matter, butalso on the structure of the star, i.e. on its massand radius. Indeed, it has been claimed recentlythat 511 keV photons observed by the space probeINTEGRAL from the galactic bulge may be dueto e+ e annihilation, and their source may be theposition cloud outside of an antiquark star. Exis-tence of stars may explain the antibaryon deficitof the universe. So, the surface tension for suchstars must be high enough to allow for survival ofquark/antiquark stars born in early stages of theformation of the universe. We studied the surfacetension of strange stars and the Newtonian andgeneral relativistic contributions to the same.

It appears that there is a genuine shortage ofradio pulsars with surface magnetic fields signifi-cantly smaller than ∼ 108 Gauss. It has been pro-posed that pulsars with very low magnetic fieldsare actually strange stars. It is shown that super-conducting super fluid of ud, ss quark pairs in arotating strange star will permit a low magneticfield.

Work is done in collaboration with SiddharthaBhowmick, Subharthi Ray, Sushan Konar, MonikaSinha and Raka Dona Ray Mandal, Manjari Bagchiand Ashik Iqubal.

Singh, K. Y.

Three distinct categories of blackhole systems havebeen identified as of today : X-ray binaries, Ac-tive Galactic Nuclei (AGNs), Ultra-luminous X-raysources (ULXs). X-ray binaries are black holes andneutron star systems which are accreting matterfrom a regular star. They constitute the brightestclass of X-ray sources in the sky. AGNs are alsostrong sources of high energy photons generated byviscous dissipative processes in the accretion disk

of a super massive blackhole. The most salientproperties of AGNs are high luminosity (1040 -1046 ergs/s) and strong optical emission lines withlarge line widths (upto 104 km/s). X-ray binariesand AGNs have been well studied in the last fewdecades and their exact nature, to a large extent,are well understood. On the other hand, ULXs,the third black hole system, which are basicallynon-nuclear, very bright, point like sources withintrinsic luminosity (> 1039 ergs/s) have been dis-covered recently (by the Einstein satellite in 1989).Due to lack of combination of a very good angularresolution and moderate spectral resolution of de-tectors in the past X-ray missions, the ULXs werepoorly studied in the last 10-15 years. With X-ray missions like ROSAT, ASCA, XMM and mostimportantly with the advent of CHANDRA, theULXs have become much more revealed and theirproperties are being studied more rigorously. How-ever, the study of the ULX may be said to be still inthe infant stage as their physical properties are notyet clearly confirmed and still in controversy. Theyneither belong to the stellar mass (< 20solarmass)X-ray binaries nor they belong to super massiveblack hole systems (106-1010 solar mass) AGNs.The ULXs are associated with ‘intermediate massblack holes’ (IMBHs) (102-105 solar mass) whichrepresent the missing component of the above BHmass spectrum. Therefore, it is expected that adetailed study of the properties of the ULXs andalso a comparative study of the spectral proper-ties of the ULXs, X-ray binaries and AGNs willenhance our understanding of these BH-systems asa whole. K. Y. Singh and some of his Ph.D. stu-dents are presently studying some ULXs using theChandra ACIS galaxy data available in the CXCarchive. The data reduction and analysis are beingcarried out using CIAO3.2 and LHEASOFT5.3.1tools. The spectral fitting package XSPEC11.3.1has been used for spectral analysis of events.

Besides working on data analysis and inter-pretations of ULXs archive data, K. Y. Singh ispresently engaged in an ongoing DST project en-titled “Development of Stellar Photometric Obser-vation Facility at Manipur University”. With theassistance of a JRF of the project L. DharendraSingh, Singh has successfully established an astro-nomical observational facility at Manipur Univer-sity equipped with a Celestron CGE 9.25” telescopeand a SBIG ST-7XME Camera Delux Package. Us-ing this observational facility, Singh has carried outthree outreach programmes for school and collegestudents. Singh and his JRF of the project arealso presently taking observations on some variablestars. Two Ph.D. students A. Senorita Devi and I.Ablu Singh working under the supervision of Dr.Singh have already passed the IUCAA-NCRA one

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year graduate Pre-Ph.D. programmes held at IU-CAA, Pune.

Stars, Stellar Systems and In-terstellar Medium

Chandra, Suresh

Suresh Chandra and his research group is activelyinvolved in radiative transfer calculations in asym-metric top molecules. They want to use the anoma-lous absorption - absorption against the cosmic mi-crowave background, as a technique for identifica-tion of molecules in cool cosmic objects. The ki-netic temperature in cool cosmic objects may notbe sufficiently high to generate the emission spec-trum of the molecules present there. However,these molecules may be identified in absorption,as their lower energy levels are always populated.Some transitions in asymmetric top molecules, mayshow anomalous absorption. In the case of theanomalous absorption, the brightness temperatureof radiation is smaller than that of the cosmic mi-crowave background, 2.73 K. The idea behind iden-tification of as many molecules as possible, is tohave better understanding about the physical con-ditions prevailing in the cool cosmic objects andto know more about the chemical reactions goingon there. The group has investigated a number ofmolecules and further work is in progress.

Chattopadhyay, Asis Kumar

Asis Kumar Chattopadhyay has carried out an ob-jective classification for the globular clusters in ourGalaxy, LMC and M31 by a new method of clus-ter analysis (CA) and the set of parameters for thismethod has been selected through an objective pro-cess, Principal Component Analysis (PCA). Theclusters exhibit multimodality, unlike bimodalityfound in many spirals and giant ellipticals withrespect to only one parameter colour/metallicity.This work was done in collaboration with TanukaChattopadhyay.

Pandey, S. K.

A detailed analysis of photometric data on five sus-pected active stars, namely, HD85945, HD20277,HD39286, HD88639, and HD191179 selected on thebasis of their intense X-ray emission, were carriedout. Low-resolution spectroscopic observations inH-alpha and CaII Infrared triplet(IRT) of thesestars carried out using HCT 2m telescope at Hanleduring 2004-2005 for seven nights were also an-alyzed. All stars except HD85945 are found to

exhibit significant photometrc variation typical ofspotted stars. All except HD85945 are also foundto show variable absorption/emission in H-alphaand CaII IRT region. This together with the ob-served photometric variation seen in the four of thefive stars suggest that these are variable stars pos-sibly belonging to the class of chromosphericallyactive stars. This work formed a part of Ph. D.thesis of Sudhanshu Barway, who has submittedhis thesis in December 2005 to the University.

Rastogi, Shantanu

The mid IR emission features at 3050, 1610, 1310,1165 and 885 cm−1 (3.28, 6.2, 7.7, 8.6 and 11.2 μm)are ubiquitous in a variety of interstellar regionsviz., Planetary Nebulae, proto-Planetary Nebulae,reflection Nebulae, H II regions and even in ex-tra galactic sources. The IR features are a result ofemissions from a family of Polycyclic Aromatic Hy-drocarbon (PAH) molecules consisting of neutrals,cations, anions and hydrogenated/de-hydrogenatedspecies. These Aromatic Infrared Bands (AIBs)show source to source variations in the IR bandsrelated to the type of PAHs present in the sur-rounding medium. Spectral variations with shape,size and ionization state of PAHs have been stud-ied by Amit Pathak and Shantanu Rastogi to get abetter understanding of the interstellar spectra. Asystematic study of several PAHs and their cationshas been done using ab-initio density functionalmethod. The variation in intensity of IR bandsupon ionization is related to the change in chargedistribution within the molecules. The C-H stretchintensity increases as the partial charge on the Hy-drogen atoms in the PAH decreases. Theoretical IRspectra for catacondensed and pericondensed PAHsin both neutral and ionic forms show that largecompact PAH cations are preferred in the ISM.Study of very large PAHs (having > 30 C atoms)has been done using the High Performance Com-puting facility at IUCAA. Co-added spectra of dif-ferent groups of PAHs have been used to model theobserved composite AIB features. More neutralsand medium sized pericondensed PAHs seem to bewithin the benign atmospheres around AGB starsand proto-Planetary Nebulae, while large PAHcations are probable in the harsh environments ofstar forming regions.

Sen, Asoke Kumar

The polarization observed for stars background todark clouds (Bok Globules) is often used as di-agnostic to study the ongoing star formation pro-cesses in these clouds. Such polarization maps inthe optical were reported for eight nearby clouds

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CB3, CB25, CB39, CB52, CB54, CB58, CB62 andCB246 in an earlier work (Sen et al. 2000, A&AS,141, p175). In a recent work (Sen, Mukai, Guptaand Das 2005 MNRAS, 361, p177), the relationsbetween this observed polarization and other phys-ical parameters in the cloud (like temperature, tur-bulence, etc.) have been studied. The observed po-larization does not seem to be clearly related to thedust and gas temperatures (TdandTg) in the cloudas expected from Davis-Greenstein grain alignmentmechanism. However, the average observed polar-ization (pav) appears to be related to the gas tur-bulence V (measured by 12 CO line width) by themathematical relation pav =2.95exp (−0.24 ∗ V )as derived in the present work. The possible re-lation between the direction of polarization vectorand other physical parameters have been also stud-ied. In order to study the spatial distribution of thedegree of polarization and position angles acrossthe different parts of the cloud, a simple modelwas proposed, where the cloud has been assumedto be a simple dichroic polarizing sphere and thelight from the background star first passes throughthe IS medium and then through the cloud, beforereaching the observer. The polarizing sphere con-tains several layers of dichoric sheets having samepolarizing properties as that of IS medium. Thismodel could successfully explain the observed po-larization for the above star forming clouds.

Singh, H. P.

The Indo-US coude feed stellar spectral library(CFLIB) made available to the astronomical com-munity recently by Valdes, et al. (2004) containsspectra of 1273 stars in the spectral region 3460to 9464 A at a high resolution of 1 A FWHMand a wide range of spectral types. Cross-checkingthe reliability of this database is an important anddesirable exercise since a number of stars in thisdatabase have no known spectral types, and a con-siderable fraction of stars has not so complete cov-erage in the full wavelength region of 3460-9464A resulting in gaps ranging from a few A toseveral tens of A . Harinder P. Singh in collabo-ration with Ranjan Gupta and their counterpartsManabu Yuasa and N. Yamamoto, used an au-tomated classification scheme based on ArtificialNeural Networks (ANN) to classify all 1273 starsin the database. In addition, principal componentanalysis (PCA) was carried out to reduce the di-mensionality of the data set before the spectra areclassified by the ANN. Most importantly, they suc-cessfully demonstrated employment of a variationof the PCA technique to restore the missing datain a sample of 300 stars out of the CFLIB.

Sun and the Solar System

Badruddin

Badruddin and coworkers have examined galacticcosmic ray (GCR) intensity from ground-based andspace-borne experiments and identified a numberof transient depressions lasting several days. Af-ter classifying them into different categories, theyutilized solar data, and analyzed interplanetaryplasma/field data, to search for the solar and in-terplanetary causes of the observed depressions inGCR intensity. By examining and analyzing simul-taneous variations in solar wind plasma speed, den-sity and temperature, along with the interplanetarymagnetic field, its magnitude and fluctuations init, they have identified possible structures such asmanifestations of coronal mass ejections in inter-planetary space, shock/sheath regions formed dueto compression of ambient magnetic field by highspeed mass ejections, interaction regions formed byinteraction between slow and high speed solar wind,compression region formed due to interaction ofhigh speed streams from coronal holes with slowmoving coronal mass ejections. They have studiedthe relationship between GCR intensity and var-ious solar wind parameters during the passage ofthese structures of distant plasma and field char-acteristics. From their analysis they could suggestpossible physical mechanisms playing major role inproducing different types of depressions in GCR in-tensity.

Kumar, Nagendra

The heating of the solar corona by MHD waveshas been investigated by Nagendra Kumar, in col-laboration with P. Kumar and S. Singh. Takinginto account dissipation mechanisms viscosity andthermal conduction, a general dispersion relationof fifth order for MHD waves has been derivedand solved numerically. It is found that the dis-persion relation results three modes namely slow,fast, and thermal. The damping of both slow andfast-mode waves depends upon the plasma density,the temperature, the magnetic field strength, andthe angle of propagation relative to the backgroundmagnetic field. Slow-mode waves contribute to theheating of the solar corona, if one considers thatthey are generated in the corona by turbulent mo-tions at magnetic reconnection sites. Calculationsof wave damping rates determined from the disper-sion relation indicate that slow mode waves withperiods of less than 60 seconds damp sufficientlyrapidly and dissipate enough energy to balance ra-diative losses, whereas the fast mode waves withperiods less than 3 seconds may damp at rates great

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enough to balance the radiative losses in active re-gions. In the case of magnetic coronal loops, itis observed that slow mode waves with frequen-cies greater than 0.003 Hz and fast mode waveswith frequencies greater than 0.28 Hz (high fre-quency) are needed for coronal heating and to bal-ance the radiative losses in active regions. Nagen-dra Kumar along with Pradeep Kumar has stud-ied the damping of MHD waves in solar coronalmagnetic field, taking into account thermal con-duction and compressive viscosity as dissipativemechanisms. The dispersion relation results intothree wave modes: slow, fast, and thermal modes.Damping time and damping per periods for slowand fast mode waves determined from dispersionrelation show that the slow mode waves are heav-ily damped in comparison with fast mode wavesin prominences, prominence-corona transition re-gions, and corona. In prominence-corona transi-tion regions and coronal active regions, wave insta-bilities appear for considered heating mechanisms.For same heating mechanisms in different promi-nences the behaviour of damping time and dampingper period changes significantly from small to largewave numbers. In all prominence-corona transi-tion regions and corona, damping time always de-creases linearly with increase in wave number indi-cate sharp damping of slow and fast mode waves.

Narain, Udit

Udit Narain and his group have been carrying onresearch on heating of solar and stellar coronae.The latest work concerns heating of solar corona bynano- and microflares, which are explosive events ofmagnetic reconnection. Each event releases energyin the range 1022 to 1026 ergs.

They have started work on environmental ef-fects of coronal mass ejections (CMEs) in whichbillions of tonnes of solar material is thrown awayinto the interplanetary space from the solar sur-face. These CMEs travel at a speed of about 300 to2000 km/s towards earth. On reaching earth’s mag-netosphere they disturb the distribution of mag-netic field in the earth’s atmosphere. The energeticCMEs can cause power break-down in terrestrialpower stations. They can damage satellites andare hazardous to humans, animals and vegetation.Thus, their study is quite important.

Prasad, Lalan

Lalan Prasad has reinvestigated the work of Narainand Kumar (1995) and overcome the inconsisten-cies present in it. The variation of total electro-dynamic coupling efficiency E and its non-resonantcomponent with loop length l for four different dis-

sipation times are discussed. He also discusses thevariation of resonant heating efficiency E with dissi-pated time for four different loop lengths. He foundthat there was decrease in the heating efficiency forlarge values of l. The variations are not so steepand large, as shown by Narain and Kumar (1995)in their figures. There is one peak in each graphhowever, Narain and Kumar (1995) have found twopeaks. Thus, the AC component of heating playsimportant role for loops of lengths l > 109.25cm.The AC component for m = 1 is the most effectivefor the loop lengths ∼ 109.7cm and the componentfor m = 2, 3 and 4 show peak for large value ofl. The AC component of heating efficiency playssignificant role for long coronal loops.

Sahijpal, Sandeep

The planetary differentiation of terrestrial planetsinto iron-core with silicate-mantle and silicate-crustoccurred within the initial 30 million years in theearly solar system. The differentiation processesinitiated prior to the accretion of the terrestrialplanets, while they were still in the (10-100 kmsized) planetesimal stage. Based on the detailedanalyses of iron and stony-iron meteorites, thereis a substantial evidence to support the early dif-ferentiation of planetesimals. Heat generated duethe decay energy of the two short-lived nuclides,26Al and 60Fe, in the early solar system is consid-ered to be responsible for the planetary differen-tiation. S. Sahijpal has performed comprehensivenumerical simulations of the planetary differentia-tion of planetesimals undergoing a linear accretiongrowth. The two short-lived nuclides were consid-ered as the heat sources. The gradual growth ofthe iron-core during the segregation of iron fromthe melting planetesimal was numerically modeledfor the first time according to the thermal evolutionof the accreting planetesimal. The extrusion of thebasaltic melts to form a crust has been also para-metrically modeled for the first time to understandthe most primitive volcanic activities in the solarsystem. In order to have significant melting forplanetary differentiation, the accretion of the plan-etesimal should commence within the initial coupleof million years in the early solar system. Depend-ing upon the accretion scenario and the planetarydifferentiation criteria, the growth of the iron-coreand the silicate melting in a planetesimal can pro-long for the initial 10 million years.

Sen, Asoke Kumar

In collaboration with Institute for Planetary Re-search, German Aerospace Centre (DLR), Berlin,some photometric observations (November 2005)

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were carried out with the Himalayan Chandra Tele-scope (HCT) under the IUCAA’s guest observingprogramme to study the Karin cluster of asteroids.The Karin cluster is by far the youngest knownfamily of main-belt asteroids, dating back to a colli-sional event only 5.8 Myr ago. The main aim of theobservations include a study of trends in thermalinertia and albedo with size. This in turn will helpto answer questions like : Are the distributions ofsizes and albedos compatible with the Karin clus-ter being the result of a single catastrophic collision5.8 Myr ago? The data are now being analysed.

Shrivastava, Pankaj K.

Pankaj K. Shrivatava and his coworkers have stud-ied the latitudinal and longitudinal distribution ofsolar flare events of high importance around the sunand their effects on cosmic ray modulation. A largenumber of solar flares in the western hemisphere arefound to be associated with Forbush decreases ofcosmic rays intensity. Forbush decrease events areidentified in hourly plots of neutron monitor data.Forbush decreases are transient decreases of cosmicrays. Such decreases are followed by a slow recov-ery typically lasting for several days. They haveutilized the Coronal Mass Ejections (CMEs) datato derive their impact on cosmic ray modulation.Adopting the chree analysis of superposed epochmethod, they have also studied the effects of CMEsand solar flares on geomagnetic activity for the pe-riod of solar cycles 22 and 23. The average charac-teristics of the diurnal and semi-diurnal anisotropyof cosmic ray intensity at realistic energies havebeen obtained by using data from world wide gridof neutron monitor for the period 1989 to 2003.The complex behaviour of diurnal amplitudes andtime of maxima (phase) and its association withAp index on a long-term and day to day basis havebeen studied. On a long-term basis, the correlationof diurnal variation with Ap index have been foundto vary during the solar cycle. On a short-term ba-sis, it has been observed that the high Ap daysare usually associated with higher amplitudes withphase shifted to early hours. It is well known thatone of the most dynamical feature in interplanetaryspace is high speed solar wind streams (HSSWS).Shrivastava has derived a significant effects of thesestreams on geomagnetic field variation as well ason transient decreases in cosmic rays. Relationshipbetween cosmic ray intensity and tilt of the helio-spheric current sheet has been carried out for A >0 and A < 0 epochs of solar magnetic field for theperiod 1980 to 1999.

Plasma Physics

Khan, Manoranjan

Pure pair-ion plasma composed of positive andnegative ions with an equal charge to mass ratiohas been recently created in the laboratory. Theion thermal waves in a pair-ion plasma with equalion-to-charge mass ratio can be modulated due totheir coupling with quasistationary density pertur-bation. Modulated ion thermal waves in such aplasma can be localized and trapped in a self cre-ated ion density hole. This work has been donein collaboration with P.K. Shukla during the visitof M. Khan under INSA-Deritsche For Schungsge-meinschaft (Germany) exchange programme to theRuhr Universitat (Germany).

In a dusty plasma (or complex plasma), sec-ondary electron emission leading to the enhance-ment of the electron number density is an im-portant phenomenon in astrophysical bodies, iono-spheric layers, etc. The existence of the steadystate for the dusty plasma is possible through com-pensation of ambient electron and ion density varia-tion due to their attachment to the dust grains. Onthe other hand, in a dusty plasma containing neu-tral atoms, replenishment of such losses are likely tooccur through ionization-recombination phenom-ena.

The effects of all these processes on dust ionacoustic wave propagation are investigated in col-laboration with M.R. Gupta, S. Sarkar, B. Roy andA. Karmakar.

The role of negative ions is also an impor-tant phenomenon in a complex plasma (or dustyplasma). The dust acoustic wave propagation hasbeen studied in a complex plasma consisting ofBoltzmann distributed electrons, positive and neg-ative ions and negatively charged dust grains whengrain charge fluctuations are taken into account.The presence of negative ions is found to be an ad-ditional component, which may occur naturally ormay be injected from external sources in space orlaboratory plasma. The grain charge fluctuationeffect is responsible for damping of dust acousticwave in absence of negative ions. It has been ob-served that the negative ions significantly reducesthe damping effect as well as the real frequency.The low temperature negative ions are also respon-sible for this reduction process. Presence of nega-tive ions in a complex plasma also contribute tonegative ion current to the grain charging mecha-nism. This work has been done in collaborationwith M. R. Gupta, S. Sarkar, B. Roy and withthe scientists of the Institute of Plasma Research,Gandhinagar.

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Dynamics

Ambika, G.

G. Ambika, in collaboration with K. P. Harikrish-nan, has conducted extensive studies on stochas-tic resonance (SR) and its characteristic featuresin three model systems viz., Josephson junction,bimodal cubic map and coupled map lattice. Itis found that a model Josephson system can func-tion both as bistable and threshold systems and candetect effectively subthreshold signals and compos-ite signals with multiple frequencies under suitabletuning of input or inherent noise. That stochasticresonance can be used as a filter for multi signal in-puts, which is established in the case of cubic mapsalso. A fundamental difference between the SR inbistable and threshold systems is that while theformer transmits the constituent frequencies alone,the latter permits detection of the difference fre-quency also.

The different types of resonance phenomenathat can occur in a coupled map lattice (CML)in the presence of noise and a sub threshold sig-nal are analysed with an onset bisatble dynamics.In addition to the conventional SR observed in thetemporal iterates, the possibility of a spatial or lat-tice stochastic resonance (LSR) is established in thespatial sequences along the lattice. The character-izing features in both are analysed in detail underdifferent types of spatially varying signals, travel-ing waves, etc. The work is suggestive of practicalapplications possible in signal detection, image pro-cessing and communication networks.

Harikrishnan, K. P.

Harikrishnan, K. P., along with G. Ambika, R.Misra and A. K. Kembhavi, has done a detailednonlinear time series analysis of the light curvefrom the black hole system GRS 1915+105. Us-ing surrogate analysis and singular value decompo-sition (SVD) technique, they have given evidencefor nonlinearity in the temporal behaviour of theblack hole system.

Harikrishnan K. P. has also done some workrelated to the phenomenon of stochastic resonancein coupled map lattice. Along with G. Ambika andKamala Menon, he has introduced the novel con-cept of “Lattice Stochastic Resonance” in coupledmap lattice.

Kuriakose, V. C.

Studies on propagation of electromagnetic wavesthrough optic fibres find very wide applications. Inmany situations ideal fibres are considered. P.A.Subha and V. C. Kuriakose have studied wave

propagation through realistic fibres. We have con-sidered an inhomogeneous optic fibre with fre-quency chirping. The wave propagation throughsuch a fibre is studied using variational analysisand numerical methods and found that adiabaticcompression of solitons can be achieved in such sys-tems. Recently, the study of formation solitons inbulk media is gaining interests. We have also stud-ied the case of solitons in bulk media with varyingdiffraction and nonliearity management using vari-ational and numerical methods and found the con-ditions under which such a system can support spa-tial solitons. C. P. Jisha and V.C. Kuriakose haveshown the existence of light bullets in a mediumwith cubic-quintic nonlinearity and self defocusingeffect of free electrons due to plasma polymerisa-tion using analytic and numerical methods, andlight bullets find application in optical communica-tion. The study of dynamics of Josephson junctionsis a topic of interests to both theoretical as well asexperimental physicists. The interaction of Joseph-son junctions with external fields has played impor-tant role in the development of Josephson junctionand its chaotic dynamics. Chitra R. Nayak and V.C. Kuriakose have studied the effect of phase dif-ference of the applied fields on mutually coupledJosephson junctions and found that by applying aphase difference in the driving fields, we can controlchaos in Josephson junctions and also obtained thejunction parameter values to achieve the same.

Mittal, A. K.

A. K. Mittal, S. Dwivedi and R. S. Yadav appliedan invariant manifold technique, to obtain the re-turn map for the maximum value of the variable xof the Lorenz model. They used this return mapto derive the regime transition rules discovered em-pirically by them earlier. They applied the Perron-Frobenius algorithm over this return map to esti-mate the probability distribution for number of cy-cles between successive regime transitions. Theyalso obtained this probability distribution for aforced Lorenz model that was introduced by Palmeras a conceptual model to explore the effects of seasurface temperature on seasonal rainfall.

The regime transition rules obtained by themfor the Lorenz model and some other two-regimeattractors had earlier led them to conjecture pos-itive correlation between magnitudes of maximumanomaly during active rainfall spell and durationof subsequent break spells. S. Dwivedi, A. K. Mit-tal and B. N. Goswami analyzed several data-setspertaining to Intra-Seasonal Oscillations and foundsignificant positive correlation between these twovariables. They also proposed a method of mak-ing extended range prediction of duration of Indian

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summer monsoon breaks. They further showedthat a stochastically forced Lorenz model exhibitssome of the salient features of Indian summer mon-soon intra-seasonal oscillations.

Vishwakarma, J. P.

The study of converging shocks in a non-uniformmedium is applicable to the motion of shock wavesin outer layer of a star, where the density goes tozero. J. P. Vishwakarma, in collaboration with S.Vishwakarma has obtained the self-similar solutionof the gas dynamic equations of strong converg-ing cylindrical and spherical shock waves movingthrough an ideal gas with initial density obeying apower law. The flow behind the shock is assumed tobe adiabatic. A study of singular points of the dif-ferential equations leads to an analytic descriptionof the flow and a simple determination of the sim-ilarity exponent, which is in excellent agreementwith the earlier values obtained by sophisticatedanalytic or numerical methods.

The problem of shock wave propagation in adusty gas is of importance in the study of a colli-sion flow pattern of a coma with a planet. J. P.Vishwakarma, in collaboration with A. S. Rai ob-tained the shock velocity and effective shock Machnumber for a shock wave propagating in a dustygas by using Whitham’s rule. The initial densityand temperature of the medium are assumed to bedecreasing exponentially. The results are discussedfor different values of mass concentration of solidparticles in the dusty gas, the ratio of density ofsolid particles and that of initial gas at the origin,and the index of variation of initial temperature.

Theoretical Physics

Gangal, Anil

Anil Gangal together with Seema Satin and AbhayParvate has obtained a diffusion equation on fractalcurves. An equivalent of Chapmann-Kolmogorovequation was proposed, which was expanded usingfractal Taylor series. It results in an equivalentof Kramers-Moyal expansion, from which Fokker-Plank equation for such curves follows. For a suit-able transition probability on fractal curves, thediffusion and drift coefficients can be calculated andlead to the fractal diffusion equation. Such equa-tions provide a framework for dealing with diffusionon fractal paths.

Gaur, Naveen

Naveen Gaur has studied the signatures of newphysics in various semi-leptonic decays of B-meson.

A study of purely dileptonic and radiative decaymode was carried out within the context of twoHiggs doublet (2HDM) model and Supersymmet-ric (SUSY) model. In another work, the study ofsensitivity of the position of zero of the ForwardBackward (FB) asymmetries in B → K∗�+�− in amodel independent framework was done. Continu-ing the study in semileptonic B-decays, the studyof CP violating signatures in B → K�+�− was alsocarried out in a model independent fashion. Inanother work, he tried to constrain the possibil-ity of lepton number violation in Little Higgs (LH)model. For this, he considered the experimentalresults on (g − 2)μ and μ− → e−e+e−. The workwas done in collaboration with S. Rai Choudhary,A. S. Cornell and G. C. Joshi.

Goyal, Ashok

Ashok Goyal, with S.R. Choudhury, Naveen Gaurand Sukanta Dutta has been investigating phe-nomena and processes likely to point towards newphysics beyond the standard model. K0-K0 barmass difference, lepton number violation and neu-trino Majarona mass generation in Little Higgsmodel. Bounds on lepton number violation fromneutrinoless double beta decay, meson and lep-ton decays, trimuon production in neutrino factory,anamolous magnetic moment of muons. In additionthey have been studying the signals of LH modelin gamma- gamma scattering. Triple vector-bosonanamolous coupling are some other phenomenonunder consideration.

Kaushal, R. S.

In the development of theoretical sciences, the useof harmonic oscillator potential (a manifestation ofsimple pendulum) or its variants has often becomean important tool for the purposes of testing theformulated underlying theories in different fields.R. S. Kaushal has made a survey of such applica-tions of the oscillator potential in the context ofmathematical, conceptual, conventional and engi-neering disciplines, besides the one in mathemat-ical physics. From the point of view of puttingthe available knowledge in a nut-shell, such analo-gous applications of the pendulum are brought to-gether and discussed by Kaushal as an example ofstructural analogy. With a view to classifying theanalogies in a philosophical domain, the conceptof structural analogy is introduced by Kaushal inhis earlier publications. In conclusion, Kaushal hassuggested a new dimension of thinking for theoreti-cal physicists by way of analyzing and subsequentlygeneralizing the Chevreul’s hand-held pendulum.

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In another ongoing project, Kaushal, in collab-oration with D. Parashar, A. K. Sisodiya and V. S.Bhasin, has also pursued his studies on nonstrangeand strange diquark (dq) stars within the frame-work of an effective phi-4 field theory. Two-diquarkinteraction energies in the quark-gluon plasma areexplicitly calculated within the framework of theconstituent quark model and a generalized Pauliprinciple. Equations of state for the diquark matterfor a variety of dq-dq couplings are derived and sub-sequently the Tolman-Oppenheimer-Volkoff equa-tions for the masses and radii of diquark stars aresolved.

Kuriakose, V. C.

The discovery made by Hawking that small blackholes can radiate energy implies that black holescan exist in thermal equilibrium with a heat bathcomposed of quantum fields interacting with theblack hole geometry. P. I. Kuriakose and V. C.Kuriakose have studied the back reaction at thecosmic horizon of Schwarzschild - de Sitter blackhole in thermal equilibrium with conformal mass-less quantum field. They have determined theeffect of back reaction by solving Einstein’s fieldequation. They have also studied the problemby evaluating the perturbed potential in the pres-ence of a quantum field using the Hamilton-Jacobimethod and obtained stable and unstable orbitsfor massive and massles particles. Sini and Kuri-akose have studied scattering of scalar particles bya Schwarzschild - de Sitter black hole by consider-ing reflection of waves at the black hole horizon.Reflection of waves at the horizon may not be pos-sible classically, but it can take place quantum me-chanically.

Mukherjee, Pradip

Reparametrization invariant theories occupy a veryspatial space in theoretical physics for their occur-rence in string theory, general relativity and quan-tum gravity. From the point of view of constrainedsystems, such theories are categorized as alreadyparameterized. There exists a deep connectionbetween gauge symmetries of such theories withreparametrization invariance. This connection canbe conveniently explored by an interpolating actiontechnique introduced in recent past.

P. Mukherjee, along with R. Banerjee and A.Saha has studied a bosonic p-brane in the interpo-lating Lagrangean scenario. Specifically, they havedemonstrated the transition to Polyakov type ac-tion from the Nambu-Goto one and investigatedthe connection between the gauge symmetries andreparametrization symmetries of the model. The

cosmological term follows naturally in their scheme.Also, the dynamics of the structure lead to a natu-ral emergence of the A-D-M like split of the worldvolume.

The main problem of present day theoreticalphysics is physics at the Plank scale. At such highenergy, spacetime may exhibits fuzziness leadingto noncommutative behaviour. P. Mukherjee withA. Saha have studied a noncommutative Chern-Simons theory using a recently proposed closedform Seiberg-Witten map. The various forms ofthe energy-momentum tensor have been presented.It has been demonstrated that no BPS soliton ex-ists in the model. This analysis compliments theoperator approach results for the model.

Pandita, P. N.

Supersymmetry is the only known framework, inwhich the Higgs sector of the Standard Model, socrucial for its internal consistency, is natural. Amuch favoured implementation of the idea of su-persymmetry at low energies is the minimal super-symemtric standard model∼ (MSSM), which isobtained by doubling the number of states of SM,and introducing a second Higgs doublet to generatemasses for all the SM fermions and to cancel thetriangle gauge anomalies. However, the MSSM suf-fers from the so-called μ problem associated withthe bilinear term connecting the two Higgs doubletsuperfields Hu and Hd in the superpotential. Anelegant solution to this problem is to postulate theexistence of a chiral electroweak gauge singlet su-perfield S, and couple it to the two Higgs doubletsuperfields Hu and Hd via a dimensionless trilinearterm λHuHdS in the superpotential. This model,the so called nonminimal supersymmetric standardmodel ∼ (NMSSM) contains a lepton number vi-olating trilinear superpotential coupling, which hasno analogue in the MSSM with lepton number vi-olation.

P. N. Pandita has studied nonminimal super-symmetric standard model with lepton number vi-olation, together with M. Chemtob. This model,through a unique trilinear lepton number violatingterm in the superpotential, can give rise to neu-trino masses. Discrete symmetries of the ZN -type,which can allow such a lepton number violatingterm in the superpotential, and which satisfy theconstraints of the anomaly cancellation, have beeninvestigated. The implications of such a trilinearlepton number violating term in the superpotentialfor the phenomenology of the light neutrino massesand mixings have been studied in detail. Tree andone-loop contributions to the neutrino masses inthis model have been evaluated. A search for pos-sible suppression mechanism which could explain

55

neutral leptons of large mass hierarchies with max-imal mixing angles has been carried out.

Rao, Nagalakshmi

Nagalakshmi A. Rao has studied the relativisticgeneralization of the well-known Virial Theorem(VT) of classical mechanics, which applies to awide variety of systems ranging from an assemblyof ideal gas to a cluster of galaxies. In the outerspace, often a bunch of particles collapse to form agravitationally bound system. Using this theorem,the masses of the bound systems can be found. In-fact, global properties are the very essence of VirialTheorem. Interestingly, Virial Theorem is knownto have a quantum analogue. More importantly,the relativistic generalization of this theorem is in-teresting in itself, as it would establish a correspon-dence between classical physics, thermodynamics,stellar astrophysics, non-relativistic and relativisticquantum mechanics. Starting from the relativisticHamiltonian, Virial Theorem in the standard formis accomplished, which serves as a novel and elegantapproach to address bound systems.

Usmani, A. A.

The role of the strangeness degree of freedom mayplay a significant role in the physics of a neutronstar or a hyperon star, specially in the early evo-lution of the star and its cooling scenario. Thepossible Kaon condensation has been a frontier ofresearch due to this reason. A realistic study ofan infinite-body system like a dense neutron starin the framework of many-body theories requiresprecise information about the baryon-baryon forcesas its basic ingredients. We know that strangenesscan be experimentally injected in a few- and many-body bound nuclear system through the (K−,π−)reaction, for example. Hypernuclei are, thus, theunique laboratory to extract precise informationsabout these forces. This year, a complete realisticstudy of the 5

ΛHe hypernucleus has been performedusing a realistic Hamiltonian and a fully correlatedwave function that involves all dynamical corrrela-tions and the ΛN space exchange correlation. Inthis study, the behaviour of baryon-baryon andthree-baryon forces have been thoroughly investi-gated. Quantum Monte Carlo methods have beenimplemented to study all the s-shell single- anddouble- hypernuclei. This would help in pinningdown the strengths of the potentials, which willthen be used in a microscopic study of infinite-bodyneutron stars.

E-Content Development

Philip, Sajeeth

Recent advances in communication opens manynew avenues for modernising the conventional ed-ucational system. Modernisation does not meanreplacement of existing teaching and learningmethodologies. It only supplement and compli-ment them. While the chalk and blackboard teach-ing has its own merits, a lot more can be donewith an additional power-point or video presenta-tion. Recognising these possibilities, the Consor-tium for Educational Communication (CEC) in col-laboration with HP Labs and the Inter-UniversityCentre for Astronomy and Astrophysics (IUCAA),launched the Educentre project in 2005. The goalof the project is to develop necessary infrastructureto implement digital libraries in colleges and uni-versities with value added electronic content. Thecontent could be in video, audio, pdf or power-pointformats.

The first installation of the Educentre was car-ried out on February 1, 2006 at St. Thomas Col-lege, Kozhencheri, Kerala. The installation in-cludes a video capturing hardware that capturesvideo telecast by the educational satellite channelson a 24 by 7 basis. Two different tools were de-veloped for this purpose. The first one was devel-oped by HP Labs and the second one, called MediaPipeline, was developed by Ninan Sajeeth Philip,who is also the regional coordinator for the Edu-centre project in the state.

Video on demand is a feature that allows dif-ferent viewers to watch different video programmeson their machines simultaneously from a commonserver. This makes it possible for students to watchprogrammes of their choice without having to waitfor the exact times at which they are aired by thesatellite channels.

Media Pipeline is a public domain softwarebased on ffmepeg tools. It uses a temporary ringbuffer to capture and store video channels for apredefined period of time. This could be from oneday to ten days. The ring buffer is called a pipelinein analogy to the water pipeline, where water en-tering through one end remains trapped inside thepipeline until it exit through the other end. Me-dia Pipeline captures video from a preset channelcontinuously and traps it in its buffer for the pre-defined time. A user may view the programme orrecord it into his local system at any time in thispredefined period by specifying the date and timeof the programme he/she wants to view. Multipleusers can simultaneously make demands and watchprogrammes of their choice on their machines si-multaneously. Since the programmes aired by the

56

satellite channels cover different subjects, this fea-ture makes it possible for teachers and students tosave time in sorting out and permanently storingprogrammes of their choice in parallel.

Three student projects are being carried outunder the guidance of Ninan Sajeeth Philip to addmore features to the Media Pipeline. They havealready built a video library of about 30 hrs ofvideo material on “Basic Mathematics”, that of-fers a foundation course in Calculus, Algebra andsimilar topics for BSc students who did not studyMathematics in their plus two classes. The stu-dents projects mainly create interfaces for the datathat they may be easily accessed by students with-out any computer knowledge. For example, one ofthe projects creates a web interface in PHP thatinteract with a MySQL database to help the stu-dent to search for video content of his/her choicein the digital library. In addition to playing thevideo, the database provides related text materialincluding references to further reading.

In addition to Video content, interactive pdfdocuments are also developed here. A continuedevaluation model is followed to monitor the use-fulness of the tools. The interactive pdf documentconducts evaluation by asking multiple choice ques-tions and finally grading the student on the basisof his/her performance. It has the facility to giveexplanations to the wrong answers in addition toreferences and video content. The whole project ispicking up effectively and CEC is planning to or-ganise a state wide training program on e-contentdevelopment during June 2006.

Instrumentation

Dodia, Umesh

Umesh Dodia has built low cost previewer, aunique attachment to the IUCAA CCD cam-era/Photometer with multi filters slider. It has afront coated flip mirror with adjustable inclinationof mirror. The mirror can be locked with a but-ton magnet. It is very robust, since it is made upof AL casting with standard brass ring threading.Observation will be carried out in near future.

Radio Astrophysics

Kumbharkhane, A. C.

A. C. Kumbharkhane is actively engaged in thefield of radio astronomy. He has developed ra-dio astronomical image processing facility in theSchool of Physical Sciences at Swami Ramanand

Teerth Marathwada University, Nanded, with fi-nancial support from the Indian Space ResearchOrganisation (ISRO) under the RESPOND pro-gramme. He, along with Nimisha Kantharia ofNCRA, Pune, is working on the radio recombina-tion lines (RRLs) of galactic ionized regions. As apart of this programme they have taken observa-tion with GMRT and data analysis work is beingcarried out at S.R.T.M. University, Nanded. He,is collaborating with J. Bagchi (IUCAA) for inves-tigation of Radio Halo cluster A523. They havepresented the results based on this study at the29th International Cosmic Ray Conference held atNCRA, Pune.

Srivastava, P. K.

In the neighbourhoods of young bright stars, theinterstellar gas, and in particular the hydrogen,becomes ionized and gives rise to diffuse nebulaor an HII region. Compact HII regions are seento be embedded in more extended, less dense re-gions of ionized hydrogen and are mostly not vis-ible in the optical region. In the radio frequencydomain, thermal radiation from these compact HIIregions is observed in free-free continuum. Low fre-quency radio astronomy, therefore, provides infor-mation about several physical properties of theseHII regions such as kinetic electron temperatureand emission measure. P. K. Srivasatva, in col-laboration with Pramesh Rao of NCRA, has beenusing GMRT for observing and studying galacticHII regions. In their first detailed study of gi-ant HII complex W51, they have found that elec-tron temperatures in all the 11 compact compo-nents were much lower (≤5000K) than that re-ported by RRL studies (∼ 10000K). Moreover,they also inferred that 9 out of these 11 sourcesin W51 consist of two components, a dense coreembedded into an independent hotter ionized en-velope (astro-ph/0406644). In order to look intothe issue of electron temperatures derived fromlow frequency continuum study and RRL observa-tions, they have observed another set of 6 compactHII regions, in continuum at 235, 610, and 1420MHz, using GMRT during summers 2005. Theseinclude 5 compact sources (G10.15-0.34, G10.30-0.15, G12.21-0.10, G23.46-0.20, G29.96-0.02) andS53 complex. All these sources are seen to haveextended regions, from low resolution studies donebefore. The high resolution data from GMRT isunder analysis and will provide useful informationabout the electron temperatures and the structureof these compact HII regions, i.e., whether the ex-tended ionized regions are directly connected to re-spective compact sources or not.

57

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67

(IV) PUBLICATIONS

By IUCAA Academic Staff

The publications are arranged alphabetically by the nameof the IUCAA staff member, which is highlighted in thelist of authors. When a paper is co-authored by an IUCAAstaff member and a Visiting Associate of IUCAA, thename of the latter is displayed in italics.

(a) Journals

Debnath, U. B. Mukhopadhyay, and N. Dadhich (2006)Spacetime curvature coupling of spinors in earlyuniverse: Neutrino asymmetry and a possible source ofbaryogenesis, Mod. Phys. Lett. A21, 399.

Shojai, A., F. Shojai and N. Dadhich (2005) StaticEinstein universe as a quantum solution of causalquantum gravity, Int. J. Mod. Phys. A20, 2773.

Debnath, U., S. Chakraborty, and N. Dadhich (2005) ADynamical symmetry of the quasi-spherical (or Spherical)collapse, Int. J. Mod. Phys. D, 14, 1761.

Tinto, M., and S. V. Dhurandhar (2005) Time-delayinterferometry, Living Reviews in Relativity, Living Rev.Rel., 8, 4.

Mitra, S., S. V. Dhurandhar, and L. S. Finn (2005)Improving the efficiency of detecting gravitational wavesignals from inspiraling binaries: Chebyshevinterpolation, Phys. Rev. D 72, 102001.

Nayak, R., S. Koshti, S. V. Dhurandhar, and J-Y. Vinet(2006) On the minimum flexing of LISA’s arms, Class.Quantum Grav., 23, 1763-1778.

Dhurandhar, S.V., and Ligo Scientific Collaboration (~200authors) (2005) Search for gravitational waves fromgalactic and extra—galactic binary neutron stars, Phys.Rev. D, 72, 082001.

Dhurandhar, S.V. and Ligo Scientific Collaboration (~200authors)(2005) Search for gravitational waves fromprimordial black hole binary coalescences in the galactichalo, Phys. Rev. D, 72, 082002.

Dhurandhar, S.V., and Ligo Scientific Collaboration (~200authors) (2005) Upper l Limits on a stochasticbackground of gravitational waves, Phys. Rev. Lett., 95,221101.

Dhurandhar, S.V. , and Ligo Scientific Collaboration(~200 authors) (2006) Search for gravitational waves frombinary black hole inspirals in LIGO data, Phys. Rev. D,73, 062001.

Dhurandhar, S.V., R. Nayak, Sucheta Koshti, and J-Y.Vinet (2005) Stable flight formation of LISA, Class.Quantum Grav. 22, 481-488.

Gupta, Ranjan, D.B. Vaidya, J.S. Dobbie, and P. Chylek(2006) Scattering properties and composition ofcometary dust, Astrophysics and Space Science, 301,1, 21-31.

Sen, A. K., T., Mukai, R. Gupta, and H.S. Das (2005) Ananalysis of the distribution of background starpolarization in dark clouds, Mon. Not. R. Astron. Soc.,361, 177-190.

Gupta, Ranjan, Tadashi Mukai, D.B. Vaidya, Asoke K.Sen, and Yasuhiko Okada (2005) Interstellar extinctionby spheroidal dust grains, Astron. Astrophys., 441, 555-561.

Gupta, Ranjan, N.M. Ashok, Harinder P. Singh, andArvind C. Ranade (2005) A near-IR stellar spectral libraryin H band using the Mt. Abu telescope, Bull. Astron.Soc. of India, 33, 175.

Singh, Harinder P., Manabu Yuasa, Nawo Yamamoto,and Ranjan Gupta (2006) Reliability checks on the Indo-US stellar spectral library using Artificial Neural Networksand principal component analysis Publ. Astron. Soc.Japan, 58, 177-186.

Kembhavi, Ajit K., Sudhanshu Barway, and C. D.Ravikumar (2005) Lenticular and other galaxies, Bull.Astron. Soc. of India,, 33, 189.

Rawat, A., and Ajit K. Kembhavi, (2005) Morphologicalanalysis of intermediate redshift galaxies using the HST/ACS GOODS survey, Bull. Astron. Soc. of India, 33, 195.

Ravikumar, C.D., Sudhanshu Barway, Ajit Kembhavi,Bahram Mobasher, and V. C. Kuriakose (2006)Photometric scaling relations for bulges of galaxies,Astron. Astrophys., 446, 827.

Harikrishnan, K. P., R. Misra, G. Ambika, and AjitKembhavi (2006) A non-subjective approach to the GPalgorithm for analysing noisy time series, Physica D,215, 137.

Sahayanathan, S., and R. Misra (2005) Interpretation ofthe Radio/X-Ray knots of AGN jets within the internalshock model framework, Ap.J., 628, 611.

Agrawal, V. K, and R. Misra (2006) The unusual spectrumof the ultra-luminous X-ray source M82 X-1, Ap.J., 638,L23.

Narlikar, J.V. (2005) Einstein’s legacy : Relativisticcosmology, Current Science, 89, 12, 2114.

68

Padmanabhan ,T. (2005) Gravity and the thermodynamicsof horizons, Phys. Reports,406, 49.

Padmanabhan, T. (2005) Dark energy: The cosmologicalchallenge of the millennium, Current Science, 88,1057.

Padmanabhan, T. (2005) Holographic gravity and thesurface term in the Einstein-Hilbert action, Brazilian Jour.Phys. (Special Issue), 35, 362.

Padmanabhan, T. (2005) Vacuum fluctuations of energydensity can lead to the observed cosmological constant,Class. Quan. Grav., 22, L107-L110.

Padmanabhan, T. (2005) A new perspective on gravityand the dynamics of spacetime, Int. J. Mod. Phys., D14,2263-2270.

Roy Choudhury T., and T. Padmanabhan (2005)Cosmological parameters from supernova observations:A critical comparison of three data sets, Astron.Astrophys., 429: 807.

Sriramkumar L., and T. Padmanabhan (2005) Initial stateof matter fields and trans-Planckian physics: Can CMBobservations disentangle the two? Phys. Rev.D, 71,103512.

Ray, S., J.S.Bagla, and T. Padmanabhan (2005)Gravitational collapse in an expanding universe: Scalingrelations for two-dimensional collapse revisited,Mon.Not.R.Astron.Soc., 360, 546.

Jassal, H.K., J.S.Bagla, and T. Padmanabhan (2005)Observational constraints on low redshift evolution ofdark energy: How consistent are different observations?Phys. Rev. D, 72, 103503

Jassal H.K., J.S. Bagla, and T. Padmanabhan (2005)WMAP constraints on low redshift evolution of darkenergy, Mon.Not.R.Astron.Soc., Letters, 356, L11-L16.

Michele Fontanini, Euro Spallucci, and T. Padmanabhan,(2006) Zero-point length from string fluctuations, Phys.Lett., B633, 627-630.

Wyithe Stuart, and T. Padmanabhan (2006) Properties ofhigh redshift quasars-I: Evolution of the super-massiveblack-hole to halo mass ratio, Mon. Not. R. Astron Soc.,366, 1029-1036.

Sahni, Varun, and Yuri Shtanov (2005) Did the universeloiter at high redshifts ? Phys. Rev. D ,71, 084018.

Sahni, Varun, Yuri Shtanov, and Alexander Viznyuk (2005)Cosmic mimicry: Is LCDM a Braneworld in disguise ?,JCAP, 12, 005.

Shafieloo, Arman, Ujjaini Alam, Varun Sahni, and A. A.Starobinsky (2005) Smoothing supernova data toreconstruct the expansion history of the universe andits age, Mon. Not. R. Astron. Soc., 366, 1081.

Sheth, Jatush V., and Varun Sahni (2005) Exploring thegeometry, topology and morphology of large scalestructure using Minkowski functionals, Current Science,88, 1101.

Heinmuller, J., P. Petitjean, C. Ledoux, S. Caucci, and R.Srianand (2006) Kinematics and star formation activityin the zabs = 2.03954 damped Lyman- α system towardsPKS 0458-020, Astron. Astrophys., 449, 33.

Ledoux, C., P. Petitjean, and R. Srianand, (2006)Molecular hydrogen in a damped Lyman-α system atzabs=4.224, Ap.J.L, 640, 25.

Shaw, G., G. Ferland, R. Srianand, and R., N. Abel (2006)Physical conditions in the interstellar medium toward HD185418, Ap.J., 639, 941.

RodrÃ-guez, E., P. Petitjean, B. Aracil, C. Ledoux, R.Srianand (2006) Relative abundance pattern along theprofile of high redshift Damped Lyman- α systems,Astron. Astrophys., 446, 791.

Roy, N., J. Chengalur, and R. Srianand (2006)Multiwavelength investigation of the temperature of thecold neutral medium, Mon. Not. R.Astron. Soc., 365, L1.

Srianand, R., P. Petitjean, C. Ledoux, G. Ferland, and G.Shaw (2005) The VLT-UVES survey for molecularhydrogen in high-redshift damped Lyman α systems:physical conditions in the neutral gas,Mon.Not.R.Astron.Soc., 362, 549.

Ivanchik, A., P. Petitjean, D. Varshalovich, B.Aracil, R.Srianand, H. Chand, V. Ledoux, C., and P.Boisse (2005) Anew constraint on the time dependence of the proton-to-electron mass ratio:Analysis of the Q 0347-383 and Q0405-443 spectra, Astron. Astrophys., 440, 45.

Gupta, N., R. Srianand, and D. J. Saikia (2005) Outflowingmaterial in the compact steep-spectrum source quasar3C 48: Evidence of jet-cloud interaction?,Mon.Not.R.Astron.Soc., 361,451.

Gupta, N., T. Ghosh, S.Jeyakumar, D. J.Saikia, C.J. Salter,and R. Srianand (2005), Probing the radio sourceenvironments using absorption lines, Bull.Astron.Soc.ofIndia, 33, 397

Stalin, C. S, and R. Srianand,(2005) The nature of thepeculiar QSO SDSS J153259.96-003944, Bull. Astron.Soc. of India, 33, 400.

69

Brandenburg, A., and K. Subramanian (2005) Strongmean field dynamos require supercritical helicity fluxes,Astronomische Nachrichten, 326, 400-408.

Brandenburg ,A., and K. Subramanian (2005) Minimaltau approximation and simulations of the alpha effect,Astron. Astrophys., 439, 835-843.

Brandenburg, A., and K. Subramanian (2005)Astrophysical magnetic fields and nonlinear dynamotheory, Physics Reports, 417, 1-209.

Seshadri, T. R., and K. Subramanian (2005) CMBAnisotropy due to tangled magnetic fields in re-ionizedmodels, Phys. Rev. D , 72, 023004-1.

Subramanian, K., A. Shukurov, and N. E. L. Haugen(2006) Evolving turbulence and magnetic fields in galaxyclusters, Mon. Not. R. Astron. Soc., 366, 1437-1454.

Shukurov, A., D. Sokoloff, K. Subramanian, and A.Brandenburg (2006) Alactic dynamo and helicity lossesthrough fountain flow, Astron. Astrophys. Lett., 448,L33-L36.

(b) Proceedings

Bagchi, Joydeep (2005) High and Ultra-high Cosmic RayAcceleration in Structure Formation Shocks in Abell 3376Galaxy Cluster, J. Bagchi, F. Durret, G.B. Lima Neto, S.Paul, and S. Chavan, Proc. 29th International Cosmic RayConference, Pune , Vol. 3, 241.

Dadhich, N. (2005) Probing universality of gravity, eds.S. Rahvar, N. Sadooghi and F. Shojai, Proceedings of XIRegional Conference on Mathematical Physics, Tehran,May 3-6, 2004, p. 92.

Hasan, Priya (2005) Near infrared photometry of theyoung star clusters NGC 1960, NGC 2453 and NGC2384, Proceedungs of the symposium “Infrared andOptical Astronomy at Mt Abu Observatory: The PastDecade and the Future” (Guest Editors: B. G. Anandaraoand D. P. K. Banerjee), Bull. Astron. Soc. of India, 33, 151.

Hasan, Priya (2005) Near infrared photometry of theyoung star clusters NGC 1960, NGC 2453 and NGC2384, Proceedings of the 23 rd meeting of the ASI(Guest Editors: K. Subrahmanyam and D. J. Saikia), Bull.Astron. Soc. of India , 33, 311.

Padmanabhan, T. Advanced topics in Cosmology: Apedagogical introduction, GRADUATE SCHOOL INASTRONOMY: X Special Courses at the NationalObservatory of Rio de Janeiro (X CCE) AIP ConferenceProceedings, 2006, 843,111-166

Padmanabhan, T. Understanding Our Universe: Current

Status and Open Issues, Invited contribution in, ‘100Years of Relativity - Space-time Structure: Einstein andBeyond’, A.Ashtekar (Editor), World Scientific(Singapore, 2005) pp 175-204;

Sahni, Varun, Dark energy, Published in AIP Conf.Proc.782, 166-187,2005

Sahni, Varun (2005) Cosmological surprises frombraneworld models of dark Energy, Proceedings of the14th Workshop on General relativity and Gravitation(JGRG14), Edited by W. Hikida, M. Sasaki,T. Tanaka andT. Nakamura, p 95 - 115.

Sahni, Varun (2005) The mysterious nature of darkenergy, Proceedings of the XI Regional Conference onMathematical Physics, Tehran, Iran edited by S Rahvar,N. Sadooghi and F. Shojai, p 15-20, World Scientific.

Srianand, R., P. Petitjean, C.Ledoux, G. Ferland, and G.Shawm (2005) Molecular hydrogen at high-z: physicalconditions in protogalaxies: Probing galaxies throughquasar absorption lines, IAU Colloquium Proceedingsof the International Astronomical Union 199, Shanghai,People’s Republic of China, edited by Peter R. Williams,Cheng-Gang Shu and Brice Menard.Cambridge: Cambridge University Press, pp.168-173

Chand, H., R. Srianand, P.Petitjean, and B. Aracil (2005)Probing the variation of the fine-structure constantusing QSO absorption lines: Probing galaxies throughquasar absorption lines, IAU Colloquium Proceedingsof the International Astronomical Union 199, Shanghai,People’s Republic of China, edited by Peter R. Williams,Cheng-Gang Shu and Brice Menard. Cambridge:Cambridge University Press, pp.409-411.

Ledoux Cedric, Patrick Petitjean, Palle, Moller, JoahanFynbo, and R. Srianand (2005) The mass-metallicityrelation for high-redshift damped \lya galaxies: ProbingGalaxies through Quasar Absorption Lines, IAUColloquium Proceedings of the InternationalAstronomical Union 199, Shanghai, People’s Republicof China, edited by Peter R. Williams, Cheng-Gang Shuand Brice Menard. Cambridge: Cambridge UniversityPress, pp.433-435

Ledoux Cedric, Patrick Petitjean, and R. Srianand (2005)The VLT-UVES survey for molecular hydrogen in high-redshift DLA systems: Probing galaxies through quasarabsorption lines, IAU Colloquium Proceedings of theInternational Astronomical Union 199, Shanghai, People’sRepublic of China, edited by Peter R. Williams, Cheng-Gang Shu and Brice Menard. Cambridge: CambridgeUniversity Press, pp.436-438.

Shaw, Gargi, Gary J. Ferland, R. Srianand, and PhillipC.Stancil (2005) Molecular hydrogen in DLAs at high

70

redshift: Astrochemistry throughout the universe: recentsuccesses and current challenges, InternationalAstronomical Union. Symposium no. 231, Asilomar,California, USA. Edited by Dariusz C. Lis, Geoffrey A.Blake & Eric Herbst. Cambridge University Press.

Ledoux, C., P. Petitjean, and R. Srianand (2005) The VLT-UVES Survey for \h2 in high-redshift damped Lyman-αsystems: The Cool Universe: Observing Cosmic Dawn,ASP Conference Series, Vol. 344, Proceedings of theconference ,Valparaiso, Chile. Edited by C. Lidman andD. Alloin. San Francisco: Astronomical Society of thePacific, p.98.

Shaw, G., G. Ferland, and R. Srianand (2005) Detailedmicrophysics of H0 and its effect on the 21 cm spintemperature, AAS...20711906S

Narlikar, J.V. (2005) Astronomy, pseudoscience andrational thinking, Teaching and Learning Astronomy,Eds. Jay M. Pasachoff and John R. Percy, CambridgeUniversity Press, 164.

(c) Books (Authored)

Ranjan Gupta, Basics of Astronomy - Block I - Unit 3 -Astronomical Techniques and Basics of Astronomy -Block II -Unit 7 - Stellar Spectra and Classification,IGNOU course book PHE-15 Astronomy andAstrophysics, published by IGNOU in January 2006.

T. Padmanabhan, An Invitation to Astrophysicspublished by World Scientific, Singapore, 2006.

(d) Book Reviews

Narlikar, J.V. (2005) - Star wars amongst the dons, Areview of the book entitled Conflicts in the Cosmos:Fred Hoyle’s life in science, by Simon Mitton (Sunday,Times of India, September 4).

Padmanabhan, T. (2005) Astronomy Methods: A PhysicalApproach to Astronomical Observations by Hale Bradt,Cambridge University Press, New York., Physics Today,May 2005 p. 68.

Padmanabhan, T. (2005) Advanced Astrophysics by NebDuric, Cambridge University Press, New York., PhysicsToday, May 2005 p. 68.

Padmanabhan, T. (2005) Empire of the Stars: Friendship,Obsession and Betrayal in the Quest for Black Holes byArthur Miller, Little, Brown/Houghton Miffin, Nature,435, p. 20.

71

(a) Journals

Ambika, G., K. P. Harikrishnan, and Kamala Menon(2005) Aspects of stochastic resonance in Josephsonjunctions and coupled systems, Pramana (J Phys),64,535.

Ambika, G., Kamala Menon, and K. P. Harikrishnan(2006) Noise induced resonance phenomena in coupledmap lattices, Eur. Phys. J B, 49,225.

Ambika, G., Kamala Menon, and K. P. Harikrishnan(2006) Lattice stochastic resonance in couple map lattice-Europhys. Lett, 73(4), 506.

Singh, Y. P., and Badruddin (2006) Statisticalconsiderations in superposed epoch analysis and itsapplications in space research, J. Atmos. Sol.-Terr. Phys.,68, 803.

Singh, M., and Badruddin (2006) Study of the cosmicray diurnal anisotropy during different solar andmagnetic conditions, Solar Phys., 233, 291.

Banerjee, Narayan, and Sudipta Das (2005) Accelerationof the universe with a simple trigonometric potential,Gen. Rel. Grav., 37, 1695.

Das, Sudipta, and Narayan Banerjee (2006) Aninteracting scalar field and the recent cosmicacceleration; Gen. Rel. Grav., 38, 785.

Chakraborty, S. and U. Debnath (2005) Quasi-sphericalgravitational collapse and the role of initial data,anisotropy and inhomogeneity, Mod. Phys. Letts. A,20, 1451.

Chakraborty, Subenoy., S. Chakraborty, and U. Debnath(2005) Role of pressure in quasi-spherical gravitationalcollapse, Int. J. Mod. Phys. D, 14, 1707.

Bhanja, S., S. Chakraborty, and U. Debnath (2005)Adiabatic particle production with decaying Ë andanisotropic universe, Int. J. Mod. Phys. D, 14, 1919.

Chakraborty, S., B. C. Santra, and N. Chakravarty (2005)Viscous fluid in brane scenarios, Nuovo Cimento, 120B,451.

Chandra, Suresh, P. G. Musrif, and R. M. Dharmkare(2005) Suggestions for an interstellar C

7H

2 search, New

Astronomy, 10, 385.

Chandra, Suresh, P. G. Musrif, and Lalan Prasad (2005)Coronal heating efficiency for resonant (A.C.) and non-resonant (D.C.) mechanisms, BASI, 33, 275.

Chandra, Suresh, P. G. Musrif, S. V. Shinde, and S. A.Shinde (2005) Another suggestion for an interstellar C

5H

2

search, New Astronomy, 11, 166.

Chandra, Suresh (2005) Relation between spectroscopicconstants with limited Dunham coefficients, Pramana J.Phys., 65, 1133.

Chattopadhyay, T. and Chattopadhyay, A. K. (2006)Objective classification of spiral galaxies having extendedrotation curves beyond optical radius, AstronomicalJournal, 131, 2452.

Bagchi, M., S. Ray, M. Dey, and J. Dey (2006) Compactstrange stars with a medium dependence in gluons atfinite temperature, A & A, 450, 431.

Ray, Mandal R. D., M. Sinha, M. Bagchi, S. Konar, M.Dey, and J. Dey (2006) Strange pulsar hypothesis,MNRA S, 365, 1383.

Bagchi, M., M. Sinha, M. Dey, J. Dey, and SiddharthaBhowmick, (2005) Newtonian and general relativisticcontribution of gravity to surface tension of strange stars,A & A, Lett. 440, 33, astro-ph /0507609.

Bagchi, M., M. Sinha, M. Dey, and J. Dey (2005)Decoupling of pion coupling f pi from quarks at highdensity in three models and its possible consequences,Phys. Lett. B 618, 115.

Bagchi, M., S. Ray, M. Dey, and J. Dey (2006) Evidencefor strange stars from joint observation of harmonicabsorption bands and of redshift, MNRAS, 368, 971.

Sinha, M., A. Iqubal, J. Dey, and M. Dey, (2005)Addendum: Two new sum rules for octet-baryon magneticmoments (mu) and constraints on QCD sum rules fromnew experimental determination of mu-s for the decuplet,Phys. Lett., B 610, 283.

Cornell A. S., Naveen Gaur, and Sushil K. Singh, FBasymmetries in ß Kl+l-: A model independent approach,hep-ph/0505136.

Rai, Choudhury S., A. S. Cornell, Naveen Gaur, and T. M.Aliev CP violation in ß Kl+l-decay, hep-ph/0506188.

Rai, Choudhury S., Naveen Gaur, and Ashok Goyal, (2005)Lepton number violation in Little Higgs model, Phys.Rev. D72, 097702.

Publications by Visiting Associatesand Long Term Visitors

72

Ibohal, Ng (2005) On the variable-charged black holesembedded into de Sitter space: Hawking’s radiation, Int.J. Mod. Phys. D, 14, 973.

Ibohal, Ng, and L Dorendro, (2005) Non-stationaryrotating black holes: Entropy and Hawking’s radiation,Int. J. Mod. Phys. D, 14, 1373.

Alcaniz, J. S., Abha Dev, and Deepak Jain (2005)Constraints on the Cardassian expansion from the cosmiclens All-Sky Survey Gravitational Lens Statistics, Ap. J.,627, 1005.

Jain, Deepak, J. S. Alcaniz, and Abha Dev (2006)Observational constraints on the time-dependence ofdark energy, Nuclear Phys. B, 732, 379.

Jain, Deepak, and Abha Dev (2006) Age of high redshiftobjects - A litmus test for the dark energy models,Physics Lett. B, 633, 436.

Sethi, G., Abha Dev, and Deepak Jain (2005) Cosmologicalconstraints on the power law universe, Physics Lett. B,624, 135.

Bournaud, F., C. J. Jog, and F. Combes (2005) Galaxymergers with various mass ratios: properties of remnants,A & A, 437, 69.

Bournaud, F., F. Combes, C. J. Jog, and I. Puerari (2005)Lopsided spiral galaxies: Evidence for gas accretion, A& A, 438, 507.

Narayan, C. A., K. Saha, and C. J. Jog (2005) Constraintson the halo density profile using HI flaring in the outergalaxy, A & A, 440, 523.

Jog, C. J. (2005) Advanced mergers of galaxies: luminosityprofiles and dynamics, BASI, 33, 201.

Saha, K., and C. J. Jog (2006) On the generation ofasymmetric warps in disk galaxies, A & A, 446, 897.

Moncy, V. John (2005) Cosmography, decelerating pastand cosmological models: Learning the Bayesian way,Ap. J., 630, 667.

Tikekar, Ramesh, and Kanti Jotania (2005) Relativisticsuperdense star models of pseudo spheroidal spacetime.Int. J. Mod. Phy. D, 14, 1037.

Kaushal, R. S. (2005) The pendula in mathematicalsciences, (A Review), Ind. Journ. Pure & Appl. Phys.,43, 479.

Sisodiya, A. K., V. S. Bhasin, and R. S. Kaushal (2006)On diquark clustering in quark-gluon plasma, Pramana-J. Phys. 66, 377.

Roy, B, S. Sarkar, Manoranjan Khan, and M. R. Gupta(2005) Propagation of dust acoustic waves in a complexplasma with negative ions. Physica Scripta, 71, 644.

Shukla, P. K., and Manoranjan Khan (2005) Envelope ionthermal soliton in a pair-ion plasma. Phys. Plasma, 12,014504.

Gupta, M. R., S. Sarkar, B. Roy, A. Karmakar andManoranjan Khan (2005) Combined effect of secondaryelectron emission, plasma ion and electron numberdensity variation due to dust charging and ionizationrecombination process on dust ion acoustic wavepropagation. Physica Scripta, 71, 298.

Kulkarni, C., J. Meiring, R. Ferlet, P. Khare, J. T.Lauroesch, G. Vladilo, and D. G. York (2006) The mostmetal-rich, high H I column density intervening quasarabsorber known, Peroux, A & A, 450, 53.

York, D. G., P. Khare, and Vandenberk (2006) Averageextinction curves and relative abundances for QSOabsorption line systems at 1d” Z

abs <2, D. et al. MNRAS,

367, 945.

Jisha, C. P., V. C. Kuriakose, and K. Porsezian Spatio(2006) Temporal solitons in bulk cubic-quintic mediastabilized by self-induced multiphoton ionization, Phys.Lett. A., 352, 496.

Shaju, P. D., and V.C. Kuriakose (2006) Vortex dynamicsin S-shaped Josephson junctions, Physica C, 434, 25.

Kuriakose, P. I., and V. C. Kuriakose (2006) Back reactionin Schwarzschild-de Sitter black hole in massless quantumfield, Mod.Phys. Lett.A., 21, 169.

Shaju, P. D., and V. C. Kuriakose (2005) Double-wellpotential for Josephson vortex qubit, Physica C, 424,125.

Jisha, C. P., V. C. Kuriakose, and K. Porsezian (2005)Variational approach to spatial optical solitons in bulkcubic-quintic mediastabilized by self-inducedmultiphoton ionization, Phys. Rev. E, 71, 056615.

Mittal, A. K., S. Dwivedi, and A. C. Pandey (2005)Bifurcation analysis of a paradigmatic model of monsoonprediction, Nonlinear Processes in Geophysics, 12, 707.

Yadav, R. S., S. Dwivedi, and A. K. Mittal (2005) Predictionrules for regime changes and length in new regime forthe Lorenz model, Journal of Atmospheric Sciences, 7,2316.

Banerjee, Rabin, Pradip Mukherjee, and Anirban, Saha(2005) Bosonic P-brane and Arnowitt-Deser-Misnerdecomposition, Phys. Rev., D72, 066015.

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Bhadra, Arunava, Ion Simaciu, K. K. Nandi, and Yuan-Zhong Zhang (2005) Comments on new Brans-Dickewormholes, Phys. Rev., D 71, 128501.

Mukherjee, Pradip, and Anirban Saha (2006) A newapproach to the analysis of a noncommutative Cherns-Simons theory, Mod.Phys.Lett. A 21, 821.

Kenmoku, M., K. K. Nandi, and K. Shigemoto (2005)Analysis of black hole entropy in Brick Wall model, Class.Quant. Grav., 22, 3923.

Kenmoku, M., K. Ishimoto, K. K. Nandi, and K. Shigemoto(2006) Scalar field contribution to rotating black holeentropy, Phys. Rev., D 73, 064004.

Nandi, K. K., N. G. Migranov, J. C. Evans, and M. K.Amedeker (2006) Planetary and light motions fromNewtonian theory: An amusing exercise, Eur. J. Phys.,27, 429.

Ali, Saiyad S. K., Somnath Bharadwaj, and Sanjay K.Pandey (2006) Probing the bispectrum at the high redshiftsusing 21cm HI observations, MNRAS, 366, Issue 1, 213.

Chaware, L., S. Barway, S. K. Pandey, A. K. Kembhavi,and D. K. Sahu, (2005) Dust properties of NGC 3801:BASI, 33, 401.

Barway, S., S. K. Pandey, and L. Chaware (2005) Long-term spot activity variation in FK Comae Berenices: BASI,33, 368.

Chemtob, M., and P. N. Pandita (2006) Nonminimalsupersymmetric standard model with lepton numberviolation, Phy. Rev., D73, 055012.

Huitu, K., J. Laamanen, P. N. Pandita, and Sourov Roy(2005) Phenomenology of non-universal gaugino massesin supersymmetric grand unified theories, Phy. Rev., D72,055013.

Ananthanarayan, B., and P. N. Pandita (2005) ProbingSO (10) symmetry breaking patterns through sfermionmass relations, Int. J. Mod. Phys., A20, 4241.

Patil, K. D., and U. S. Thool (2005) Spherical and non-spherical gravitational collapse in Husain spacetime. Int.J. Mod. Phys. D, Vol. 14, 873.

Paul, B.C. and A. Beesham (2005) Power-law inflationand the cosmic no hair theorem in Brane world, Int. J.Mod. Phys. D 14, 893.

Paul, D., and B. C. Paul (2005) Primordial black hole paircreation in 1/R-gravity, Phys. Rev. D 72, 064012.

Paul, B. C., and P. S. Debnath (2005) Cosmological modelswith variable gravitational and cosmological constant inR2- gravity, Int. J. Mod. Phys. D, 15, 189.

Paul, B. C., and Ramesh Tikekar (2005) Core – envelopemodel of compact stars, Grav. & Cos, 11, 43.

Pradhan, A., A. K. Yadav, and L. Yadav (2005) Generationof Bianchi type V cosmological models with varyingLambda – term, Czech. J. Phys., 55, 503.

Pradhan, A., and Purnima Pandey (2005) Plane symmetricinhomogeneous magnetized viscous fluid universe witha variable Lambda, Czech. J. Phys., 55, 749.

Pradhan, A., S. K. Srivastav, and M. K. Yadav (2005)Some homogeneous Bianchi type IX viscous fluidcosmological models with a variable Lambda, Astrophys.Space Sci., 298, 419.

Pradhan, A., L. Yadav, and A. K. Yadav (2005) Isotropichomogeneous universe with bulk viscous fluid in Lyrageometry, Astrophys. Space Sci., 299, 31.

Pradhan, A., P. Pandey, Singh, G. P., and R.V. Deshpande(2005) Causal bulk viscous LRS Bianchi type I modelswith variable gravitational and cosmological “constant”,Spacetime & Substance, 6, 116.

Pradhan, A., and Purnima Pandey (2006) Some Bianchitype I viscous fluid cosmological models with a variablecosmological constant, Astrophys. Space Sci., 301, 127.

Pradhan, A., Purnima Pandey, and K. K. Rai (2006)Magnetized anisotropic cosmological models withvarying Lambda, Czech. J. Phys., 56, 303.

Khadekar, G. S., A. Pradhan, and M. R. Molaei (2006)Higher dimensional dust cosmological implications of adecay law for a Lambda term: The expressions for someobservable quantities, Int. J. Mod. Phys. D, 15, 95.

Rastogi, Shantanu (2005) Polycyclic aromatichydrocarbons in the interstellar medium, BASI, 33, 167.

Krot, A. N., K. D. McKeegan, G. R. Huss, K. Liffman, S.Sahijpal, I. D. Hutcheon, G. Srinivasan, A. Bischoff, andK. Keil (2006) Aluminum-magnesium and oxygen isotopestudy of relict Ca-Al-rich inclusions in chondrules, Ap.J.,639, 1227.

Yadav, J., S. Bharadwaj, B. Pandey, and T. R. Seshadri(2005) Testing homogeneity on large scales in the SloanDigital Sky Survey Data Release One, MNRAS, 364, 601.

Unnikrishnan Sanil, and T. R. Seshadri (2005) SomeConsequences of Dark energy density varying

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exponentially with scale factor, Mod. Phys. Lett., A 20,2805.

Shrivastava, Pankaj K., and N. Singh (2005) Solarlongitudinal distribution of solar flares in association withFobrush decreases, Ind. J. of Radio & Space Physics, 34,175.

Shrivastava, Pankaj K., and N. Singh (2005) Latitudinaldistribution of solar flares and their association withcoronal mass ejections, Chinese Journal of Astronomyand Astrophysics, 6, No.2, 193.

Tiwari, D. P., C. M. Tiwari, A. K. Pandey, and Pankaj K.Shrivastava (2005) Average anisotropy characteristicsof high energy cosmic ray particles and geomagneticdisturbance index Ap, Journal of Astronomy andAstrophysics, 26, 429.

Shrivastava, Pankaj K., N. Singh, and D. P. Tiwari (2005)Solar latitudinal distribution of solar flares around thesun and their association with Forbush decreases duringthe period of 1986 to 2003, Journal of Science, Iran, 16(3),277.

Singh, G. P., and S. Kotambkar (2005) Charged fluiddistribution in higher dimensional spheroidal space-time,Pramana J. Phys, 65, 35.

Usmani, A. A. (2006) Ë space-exchange correlation effectsin the Ë5He hypernucleus, Phys. Rev. C, 73, 011302(R).

Vishwakarma, J. P., and S. Vishwakarma (2005) Ananalytic description of converging shock waves in a gaswith variable density, Physica Scripta, 72, 218.

(b) Proceedings

Singh, Y. P., and Badruddin (2005) Study of cosmic raydepressions due to corotating high speed solar windstreams and their dependence on solar polarity, Proc. 29th

International Cosmic Ray Conference, Pune, 2, 73.

Gupta, V., and Badruddin (2005) Cosmic ray intensityduring Carrington rotation periods in low solar activityconditions, Proc. 29th International Cosmic RayConference, Pune, 2, 61.

Singh, M., Badruddin and A. G. Ananth (2005) Study oftime lags and hysteresis between solar indices and cosmicrays: Implications for drifts and modulation theories, Proc.29th International Cosmic Ray Conference, Pune, 2, 139.

Bagchi, J., F. Durret, G. L. Neto, S. Paul, S. D. Chavan(2005) High and ultra-high energy cosmic ray accelerationin cluster-merger shocks in Abell 3376, 29th InternationalCosmic Ray Conference, Vol. 3, 242.

Chattopadhyay, A, S. K. Sarkar, A. K. Bhattacharya, S.Giri, B. Bhattacharya, D Sarkar, and D. C. Nayak (2005)Spatiotemporal variation in benthic polychaetes(Annelida) and relationships with environmental variablesin a tropical estuary, Wetlands Ecology and Management,Kluwer Academic Publications, Netherlands, Vol 13, 55.

Chhetri, R. K., S. K. Sarkar, and K. Ghosh (2005) Indicationof change in primary at knee region from study of EASmuons at sea level, 29th International Cosmic RayConference, Edited by B.Sripathi, Sunil Gupta, P.Jagadeesan, Atul Jain, S. Karthikeyan, Samuel Morrisand Suresh Tonwar, ICRC 2005 Proceedings, 6, 141.

Sarkar, S. K., K. Ghosh, and R. K. Chhetri (2005) A studyof EAS muons near core region of showers of size 104.3 to106.3, 29th International Cosmic Ray Conference, Editedby B. Sripathi, Sunil Gupta, P. Jagadeesan, Atul Jain, S.Karthikeyan, Samuel Morris and Suresh Tonwar, ICRC2005 Proceedings, 6, 145.

Ghosh, K., S. K. Sarkar, and R. K. Chhetri (2005)Measurement of size spectra and absorption length ofEAS below and above knee of Primary, 29th InternationalCosmic Ray Conference, Edited by B. Sripathi, SunilGupta, P. Jagadeesan, Atul Jain, S. Karthikeyan, SamuelMorris and Suresh Tonwar, ICRC 2005 Proceedings, 6,149.

Goyal, Ashok (2005) Neutrino mass and lepton numberviolation in the Little Higgs model, talk given at PASCOS-05, Gyeongju, Korea, AIP Conference Proceedings,Volume 805, 302.

Tikekar, Ramesh and Kanti Jotania (2006) Exactrelativistic models of hybrid neutron star, Proceedingsof 23rd IAGRG Meeting-Jaipur, Special Issue of the Journalof Rajasthan Academy of Science, University ofRajasthan, Jaipur.

Jisha, C. P., V. C. Kuriakose, K. Porsezian, and P. A.Subha (2006) Photorefractive polymer solitons, ThirdNational Conference on Nonlinear Systems andDynamics, R. Sahadevan and M.Lakshmanan(Eds), AlliedPublishers, Chennai, 21.

Jisha, C. P., P. A. Subha, and V. C. Kuriakose (2006) Twodimensional diffractions managed soliton in cubic-quinticnonlinear media, Third National Conference on NonlinearSystems and Dynamics, R. Sahadevan and M.Lakshmanan (Eds), Allied Publishers, Chennai, 11.

Nayak, Chitra R., and V. C. Kuriakose (2006) The effectof phase of the applied field on coupled Joesphsonjunctions, Third National Conference on NonlinearSystems and Dynamics, R. Sahadevan and M.Lakshmanan (Eds), Allied Publishers, Chennai, 79.

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Dwivedi, S., A. C. Pandey, and A. K. Mittal (2005) Is therea strange attractor for Antarctic oscillation?, In India andin the Antarctic: Scientific and Geopolitical Perspectives,Eds. S. Chaturvedi, N. Khare and P. C. Pandey, SouthAsian Publishers, New Delhi, 199.

Pandey, Kumud, U. Narain, and N. K. Lohani (2005) Ontripolar magnetic reconnection and coronal heating,Proceedings of PLASMA-2004, (ed.) A. K. Singh,Allied Publishers Pvt. Ltd, New Delhi, 126.

Pathak, Amit and Shantanu Rastogi (2005) PAHs andthe Astrophysical Infrared Bands, Young AstronomersMeet, IUCAA, Pune

Pathak, Amit and Shantanu Rastogi (2005) TheoreticalIR Spectra of Large PAHs in Study of UIR Features, IAUSymposium - 231: Astrochemistry - Recent Successesand Current Challenges, Asilomar, California, U.S.A.

Tiwari, M. M. S. T., and Pankaj K. Shrivatava (2005) Halocoronal mass ejections and their geoeffectiveness, Proc.29th Int. Cosmic Ray Conf. Pune, 1, 157.

Mishra, M. P., Pankaj K. Shrivastava, and D. P. Tiwari(2005) Study of magnetic cloud events of 1996 inassociation with geomagnetic and cosmic ray intensityvariation, Proc. 29th Int. Cosmic Ray Conf. Pune, 1, 331.

Shrivastava, Pankaj K., R. P. Shukla, and R. Mishra (2005)Short–term influence of high speed solar wind streamson cosmic ray intensity variation during 1996–2002, Proc.29th Int. Cosmic Ray Conf. Pune, 1, 335.

Shrivastava, Pankaj K. (2005) Study of large solar flaresin association with Halo coronal mass ejections and theirhelio–longitudinal association with forbush decreasesof cosmic rays, Proc. 29th Int. Cosmic Ray Conf. Pune, 1,355.

Sharma, U., G. N. Singh, and Pankaj K. Shrivastava (2005)Long–term relationship between the tilt of theheliospheric neutral current sheet and cosmic rayintensity variation, Proc. 29th Int. Cosmic Ray Conf. Pune2, 179.

Tiwari, R. K., M. K. Pandey, and Pankaj K. Shrivastava(2005) A study of the role of the coronal index of solaractivity in long–term cosmic ray modulation, Proc. 29th

Int. Cosmic Ray Conf., Pune, 2, 191.

Singh, G. N., Pankaj K. Shrivastava, U. Sharma, and G.Singh (2005) Association of magnetic blobs withgeomagnetic disturbances, Proc. 29th Int. Cosmic RayConf., Pune. 2, 315.

(c) Books

Menon, Kamala, K. P. Harikrishnan, and Ambika G.(2006) Noise assisted detection of a traveling wave signalthrough a coupled map lattice in nonlinear systems anddynamics, eds-M Lakshmanan & R Sahadevan-AlliedPub.

Ambika. K., and Ambika G., (2006) Synchronisationschemes for Gumoski-Mira maps- in nonlinear systemsand dynamics, eds-M Lakshmanan & R Sahadevan-AlliedPub.

Chandra, Suresh (2006) Applications of numericaltechniques, Narosa Publishing House Pvt. Ltd., NewDelhi.

Chattopadhyay, Asis K., and Tanuka Chattopadhyay(2006) Computer Applications of Mathematics andStatistics, Asian Books Pvt Ltd, New Delhi.

Singh H. P. (Co-author), Basics of Astronomy, PHE-15module 1 of A & A, IGNOU, Delhi.

Singh H. P. (Co-author), The Solar System and Stars,PHE 15 module 2 of A & A, IGNOU, Delhi.

Singh K. Y. (2005) An Introduction to Electromagnetics,North East Publishing House, Imphal.

(d) Supervision of Thesis

Chakraborty, Subenoy (2005) Study of cosmologicalevolution in four and higher dimensional gravity,Jadavpur University, Ph.D thesis of Sri Batul ChandraSantra.

Goyal, Ashok K. (2005) Testing physics beyond thestandard model in neutrino sector, University of Delhi,Ph.D. thesis of Poonam Mehta.

Pandey, U. S. (2005) Studies in galactic clusters, D.D.U.Gorakhpur University, Ph. D. thesis of KarunakarUpadhyay.

Pradhan, A. (2005) A study on computer oriented analysisof dynamic and physical behaviour of the universe, V. B.S. Purvanchal University, Jaunpur, Ph. D. thesis of SanjayKumar Singh.

Pradhan, A. (2005) A study of some relativistic fields ofgravitational and topological defects in general relativity,V. B. S. Purvanchal University, Jaunpur, Ph. D. thesis ofOm Prakash Pandey.

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Sen, Asoke Kumar (2005) Photopolarimetric studies ofcomets and other objects, Assam University, Silchar,Ph.D. thesis of Himadri Sekhar Das.

Shrivastava, Pankaj K. (2005) Comparative study oflong–term cosmic ray modulation for odd and even solarcycles. A.P.S. University, Rewa, Ph.D. thesis of UmakantSharma.

Vishwakarma, J. P. (2005) A study of shock anddetonation waves in non-ideal gases, D. D. U. GorakhpurUniversity, Ph.D. thesis of Vinai Chaube.

Vishwakarma, J. P. (2005) A study of shock propagationin conducting and non-conducting gases, D. D.U.Gorakhpur University, Ph.D. thesis of Anil KumarMaurya.

(e) Research Projects

Chandra, Suresh, Radiative transition probabilities andanomalous absorption by molecules in cool cosmicobjects’ from the Department of Science and Technology,New Delhi

Chandra, Suresh, Anomalous phenomena in C3H andC3D cyclic molecules’ from the Indian Space ResearchOrganisation, Bangalore.

(f) Talk

Goyal, Ashok (2004) Astroparticle Physics, Plenary talkgiven at XVI DAE High energy Symposium held at SahaInstitute of Nuclear Physics, Kolkata.

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(V) PEDAGOGICAL ACTIVITIES

(a) IUCAA-NCRA Graduate School

Sanjeev DhurandharMethods of Mathematical Physics I

Ajit KembhaviElectrodynamics and Radiative Processes I

Ranjeev MisraElectrodynamics and Radiative Processes II

T. PadmanabhanExtragalactic Astronomy I

A. N. RamaprakashAstronomical Techniques I

R. SrianandGalaxies : Structure, Dynamics and Evolution

Tarun SouradeepMethods of Mathematical Physics II

(b) University of Pune

M.Sc. (Physics)

Naresh Dadhich and Varun SahniAstronomy and Astrophysics II

Ranjan GuptaAstronomy and Astrophysics I (Theory 10 lectures) andLaboratory for III and IV semester courses(10 sessions and night experiments)

J. V. Narlikar and K. SubramanianAstronomy and Astrophysics I

M.Sc. (Space Sciences)

Ranjan GuptaAstronomy and Astrophysics I (Theory 10 lectures) andLaboratory for III and IV semester courses(10 sessions and night experiments)

(c) Supervision of Projects

Joydeep Bagchi

Viral J. Parekh, M.Sc., Fergusson College, PuneThe study of nonlinear dynamics and chaos throughelectronic circuits

Nikhil Pawar, B.Sc., Fergusson College, PuneThe nature of Jovian decametric radio emissions andtheir corelation with Io.

Siddharth Hegde, B.Sc., Fergusson College, PuneThe invisible Sun: Observation and analysis of solarradiation at radio region.

Nikhil Pawar, B.Sc., Fergusson college, Pune(Joint IUCAA/NCRA VSP/VSRP Project)The study of 21 cm hydrogen line spectrum from MilkyWay galaxy.

Jaydeep Belapure, B.Sc., Fergusson College, Pune(KVPY Project)Study of meteor showers through scater of FM radiostation signals from ionization trails

Satyajit Chavan, SRTM University, NandedTraining in GMRT observations and data analysis(Long term collaborative project)

Sanjeev Dhurandhar

K. Thorat, VSP 2005General relativity and gravitational waves

S. Das, M.Sc. Univ. of PuneGravitational Waves

For a batch of four school studentsTrigonometry: applications to astronomy

Ajit Kembhavi

Anushyam Mohan, JNCASR, BangalorePhotometry and galaxy luminosity functions

Pratamesh Shenai, VSO 2005, COEP, PuneShapes of the Galaxies.

Vinu V., M.G. University, KottayamCluster of galaxies.

Harsha Naik, B.V. Bhoomaraddi College of Engg. andTech., HubliVOPlot.

Abdul Rauf, B.V. Bhoomaraddi College of Engg. andTech., Hubli,VOPlot.

Anjali Chordia, IUCAA, PunePulsar catalogue.

Abhilash Mishra, Fergusson College, PunePlanets.

78

Tarun Souradeep

Himan Mukhopadhyay, IUCAA graduate school projectCosmic spectroscopy of CMB correlation patterns.

Sharanya Sur, IUCAA graduate school projectCosmological inflation and generation of perturbation.

Yashar Akrami, M.Sc. thesis, Sharif University ofTechnology, IranPrimordial perturbations as an observational probe ofinflation.

Ehsan Khourchi, M.Sc. thesis, Sharif University ofTechnology, IranCMB anisotropy in multiply connected universes.

Tuhin Ghosh, VSP student, MSc. Indian Institute ofTechnology, KharagpurUnveiling the hidden patterns in the cosmic microwavebackground anisotropies.

Tuhin Ghosh, MSc. thesis, Indian Institute ofTechnology, Kharagpur.Cosmic microwave background anisotropies in aBianchi universe.

Mona Mostafavi , MSc. thesisWadia College, PuneDetecting symmetries in CMB maps.

Ranjeev Misra

D. Aarthi, VSP 2005Galactic center electron-positron annihilation.

J.V. Narlikar

School Students’ Summer ProgrammeFoucault pendulum.

Maheshwari Mohanty ,VSP 2005Models of universe in Newtonian cosmology.

Manan Tuli, VSP 2005Anisotropic models of the universe inNewtonian cosmology.

A. N. Ramaprakash

A. Shukla (Pune University)Wavefront aberration from defocussed images.

A. Vinodkumar, A. Attupurath, and M. Barve,Vishwakarma Institute of Technology, PuneRTC and countdown timer.

V. S. Shaiju, Mahatma Gandhi University, KeralaCryogenic stepper motors.

M. Kalamkar, Fergusson College, PuneLaboratory characterization of Princeton InstrumentsCCD camera system.

A. Kumar, Graphic Era Institute of Technology, H. N. B.Garhwal University, UttaranchalEmbedded control software for 2m observatory unifiedinstrument control system.

Varun Sahni

Maqsuda Afroze, MSc projectBasics of dark energy.

R. Srianand

Mudit Srivastava ,IUCAA-NCRA graduate school projectTime variability of associated absorption lines.

K. Subramanian

J. Sunil Kumar, VSP 2005Galactic dynamo.

(d) Supervision of Thesis

T. Padmanabhan (Guide)Sunu EngineerPhenomena in Nonlinear Gravitational Clustering.

Sanjeev Dhurandhar (Guide)Anand SenguptaEfficient Data Analysis Techniques for the Extraction ofInspiraling Binary Signals.

Varun Sahni (Guide)(Late) Jatush ShethIssues in Gravitational Clustering and Cosmology.

79

(VI) COLLOQUIA, SEMINARS,ETC.

(a) Colloquia

Atish Dabholkar: Going beyond Bekenstein andHawking (black hole entropy in string theory), April13.

Anvar Shukurov: Prehistoric demography and thespread of the neolithic: Models based on radiocarbondates, April 19.

Sumit R. Das: Gravity, holograms and matrices, June 27.

Somak Raychaudhury: The largest structures in theuniverse and their dynamical effect on us, July 7.

Tom Gehrels: Our natural inheritance and globalresponsibility, October 19.

Kameshwar Wali: Bose and Einstein, and the discoveryof their statistics, November 28.

Reza Tavakol: Inflation, oscillating universes and loopquantum cosmology, March 13.

(b) Seminars

Anvar Shukurov: Measuring interstellar currenthelicity in supernova remnants, April 7.

T. Padmanabhan: Subtle is the malice of the Lord - Anew perspective on gravity, April 20.

Vikram Soni: Neutron stars (perhaps magnetars) from asingle field theory, April 28.

Prasad Subramanian: Combining visibilities from theGMRT and the NRH: High dynamic range snapshotimages of the solar corona at 327 MHz, April 28.

Sandeep Sahijpal: Magnetic flaring and the productionof short-lived nuclei in the early solar system, May 12.

Chanda J. Jog: Vertical scale height distribution of starsand gas in a galactic disk, May 18.

Arif Babul: The evolution of the intracluster mediumwithin the hierarchical model for structure formation,June 22.

Mohammad Sami: Accelerated expansion andcosmological relevance of scaling solutions: Braneworlds, tachyons, phantoms, cosmic doomsday and allthat, July 1.

Saeed Otarod: A discussion on the devised new methodfor solving nonlinear partial differential equations, July22.

S. Mukherjee: The emerging universe in Starobinskymodel, July 27.

Sudipta Sarkar: Quantum field theory in collapsingspacetime, July 29.

Sharanya Sur: Cosmological inflation and generationof primordial perturbations, July 29.

Mudit Kumar Srivastava: Outflows from quasars: Theza = 2.082 absorption system towards quasar TOL 1037– 2703, July 29.

Himan Mukhopadhyay: Cosmic spectroscopy on CMBcorrelation patterns, August 4.

Maulik Parikh: A matter of Inertia: Mach 2, August 8.

Rosanne di Stefano: Mesolensing: Studying nearby darkand dim stars with gravitational lensing, August 9.

Urjit A. Yajnik: Magnetic domain walls of relic fermionsas dark energy, August 25.

Prathamesh M. Shenai: Shapes of the galaxies, September5.

Sanjit Mitra: CM/GW Beams, September 26.

Andrea Tartari: The cosmic microwave backgroundfrequency spectrum:Open questions and experimentalproblems, October 3.

Andrea Tartain: Coherent radiometers:A physicalperspective, October 6.

Abhishek Rawat: Morphological analysis ofintermediate redshift luminous compact galaxies usingthe HST/ACS GOODS survey, October 10.

Divakara Mayya: M82:A spiral galaxy in formation,October 14.

Alain Kerdraon: The Nancay radioheliograph: Recentresults and future developments, November 3.

Arnab Kumar Ray: A time-dependent perturbative studyof the shallow water hydraulic jump, November 8.

Dmitry Sokoloff: The maunder minimum and the solardynamo, December 8.

Amir Hajian Forushani: Cosmology through CMBanisotropy, December 9.

80

Rita Sinha: December 10.

Juergen Ehlers: The Einstein Hilbert debate, January 2.

Rob Crittenden: Probing dark energy with CMBanisotropy, January 13.

Badri Krishnan: The trapped region of a blackholespacetime, January 17.

Amrit Lal Ahuja: A novel technique of pulsar DMestimation using the GMRT, January 26.

Emmanuel Rollinde: Lithium between big bangnucleosynthesis POP III and VMPHS, January 27.

Jishnu Dey: Strange star hypothesis and its implicationfor nuclear particle phenomenology, February 3.

Francois Hammer: Evolution of the Tully-Fisher relationand scenarios of galaxy evolution, February 8.

J.E. Pringle: Spinning black holes- Which way do theypoint?, February 10.

Y.P. Viyogi: Experimental search for quark gluon plasmaand Indian contribution, February 14.

Jayanti Prasad: Gravitational collapse in an expandingbackground and the role of substructure, February 16.

Uma P. Vijh: (i) Photoluminescence by interstellar dust,and (ii) A look at the dust characteristics in the LMCusing the Spitzer Space Telescope, March 2.

K. Nakamura: Second order gauge invariantperturbation theory, March 13.

H. Maeda: Final fate of the gravitational collapse inEinstein-Gauss-Bonnet gravity, March 16.

U. Miyamoto: New stable state of inhomogeneous blackstring, March 16.

Parameter constraints using WMAP data,

81

(VII) TALKS AT IUCAAWORKSHOPS OR AT OTHERINSTITUTIONS

(a) Seminars, Colloquia and Lectures

Naresh Dadhich

Detecting extra dimensions with gravity wavespectroscopy: The black string brane-world, InformalDiscussions Group Meeting, NCRA, Pune, April 29.

Why Einstein?, Garware College, Pune, May 23.

General relativity, VSP, Pune, IUCAA, May 24, (2lectures).

Science and society, Tata Research Development andDesign Centre, Pune, May 28.

Why Einstein [Had I been born in 1844!]?, Master’sResource Training Programme organized by RashtriyaVigyan Evam Prodyogiki Sanchar Parishad, Masobra,Shimla, June 1.

Why Einstein [Had I been born in 1844!]?, Master’sResource Training Programme organized by RashtriyaVigyan Evam Prodyogiki Sanchar Parishad, Guwahati,June 15.

Science and society, Master’s Resource TrainingProgramme organized by Rashtriya Vigyan EvamProdyogiki Sanchar Parishad, Guwahati, June 16.

Why Einstein [Had I been born in 1844!]?, Saha Instituteof Nuclear Physics, Kolkata, June 17.

From Newton to Einstein, Refresher Course, Smt.Kashibai Navale College of Engineering, Pune, June 28.

Why Einstein? Master’s Resource Training Programmeorganized by Rashtriya Vigyan Evam Prodyogiki SancharParishad, Mumbai, June 29.

Why Einstein?, Second Saturday School StudentsProgramme at IUCAA, Pune, July 9.

Why Einstein?, [in Hindi] Second Saturday SchoolStudents Programme, IUCAA, Pune, July 9).

Why Einstein [Had I been born in 1844!]?, Master’sResource Training Programme organized by RashtriyaVigyan Evam Prodyogiki Sanchar Parishad, Bangalore,July 13.

IUCAA : An Experiment in propagation of astronomyin Indian universities, The 9th Asian-Pacific RegionalIAU Meeting [APRIM 2005], Indonesia, July 29.

Why Einstein?, (One-day seminar on Astrophysicsfor teachers and students, Christ College, Irinjalakuda,Kerala, August 6.

Why Einstein? (IUCAA sponsored workshop on“Exciting Astronomy : From Stars to the Universe”,University of Calicut, Calicut, Kerala, August 7.

Had things been right?, Colloquium organized byTata Institute of Fundamental Research, Mumbai inmemory of the Late Professor A.K. Raychaudhuri,Mumbai, August 10.

Why Einstein? Jadavpur University, Calcutta, August16.

Gauss-Bonnet gravity, S.N. Bose Centre for BasicSciences, Calcutta, August 17.

Why Einstein?, International Year of Physics, FergussonCollege, Pune, September 8.

Challenges of a knowledge society, Crompton GreavesManagement Development Centre, Mulshi, September17.

Why are there only four basic forces in nature?,University of Cape Town, South Africa, September22.

On the Gauss-Bonnet gravity, Physics Department,University of Cape Town, South Africa, September 23.

Curvature driven acceleration of the universe, PhysicsDepartment, University of Cape Town, South Africa,September 23.

Science and society, iThemba Laboratory, SomersetWest, South Africa, September 24.

Why Einstein [Had I Been Born in 1844!]?, A plenarytalk delivered at the Einstein Centennial Meeting at theUniversity of Kwazulu-Natal, Durban, South Africa,September 25.

Why Einstein [Had I Been Born in 1844!]?, Universityof Kwazulu-Natal, Durban, South Africa, September 30.

Why Einstein [Had I Been Born in 1844!]?, Universityof Witwatersrand, South Africa, October 3.

Why Einstein [Had I been born in 1844!]?, Universityof South Africa, October 4.

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Why Einstein [Had I Been Born in 1844!]?, YoungAstronomers’ Meet 2005, IUCAA, November 29.

Why Einstein [Had I Been Born in 1844!]?, Departmentof Physics, University of Mumbai, December 1.

Why Einstein [Had I Been Born in 1844!]?, NationalConference on “Exciting Physics of this Decade”,Department of Theoretical Physics, University of Madras,Chennai, December 2.

Why Einstein [Had I Been Born in 1844!]?, Consortiumfor Educational Communication, New Delhi, EDUSATNetwork Programme, December 5.

Why Einstein [Had I Been Born in 1844!]? First AnnualConvocation of the Indian Association of PhysicsTeachers, Kolhapur, December 11.

Raychaudhuri and his equations, InternationalConference on “Einstein’s Legacy in the NewMillennium”, Puri, December 19.

Tribute to Professor A.K. Raychaudhuri, School onCosmology and the Very Early Universe, IUCAA,December 26.

Why Einstein [Had I Been Born in 1844!]? IndianInstitute of Astrophysics, Bangalore , February 1.

Principle of universality in science, Workshop on“Foundations of Science”, National Institute of AdvancedStudies, Bangalore, February 2.

Why Einstein [Had I Been Born in 1844!]?, NehruPlanetarium, Mumbai, February 4.

Topics in gravity, (2 talks) Workshop on “Geometry,Gravity and Cosmology” at Sardar Patel University,Vallabh Vidyanagar, Gujarat, February 16.

Science and society, National Conference on “RationalThinking and Development of Scientific Temperamentin Indian Masses”, Bharatiya Jain Sanghatana College,Wagholi, Pune, February 25.

On Gauss-Bonnet gravity, Workshop and DiscussionMeeting on Black Holes, Spacetime Singularities andCosmic Censorship, Tata Institute of FundamentalResearch, Mumbai, March 5.

On Gauss-Bonnet geometry, 12th Regional Conferenceon Mathematical Physics, National Centre for Physics,Islamabad, March 31.

Sanjeev Dhurandhar

Gravitational waves, (two talks), IUCAA RefresherCourse and VSP, May-June .

Mapping the gravitational wave sky with LIGO, LIGOScience Collaboration Meeting, M. I. T., Boston, U. S.,November 20.

The quest for gravitational waves, XIV th National SpaceScience Symposium, Vishakapatnam, February 9.

LISA data analysis, Osaka National University, Osaka,Japan, February 22.

Ranjan Gupta

Dust in astrophysical environments, Department onAstronomy, Osmania University, Hyderabad, August 4.

Spectroscopy, Workshop on Observing Projects withSmall Telescopes, IUCAA, Pune August 30.

Telescopes and back-end instruments, at the NationalLevel one-day Seminar on Observational Astrophysics,Department of Physics, University of Kalyani, Kalyani,September 27.

Earth’s atmosphere, telescopes and effects , IntroductoryWorkshop: Sun and Stars, St. Xavier’s College, Kolkata,November 22.

Astronomical spectroscopy, Introductory Workshop: Sunand Stars, St. Xavier’s College, Kolkata , November 23.

Interstellar and other dust models, SNBNCBS, Kolkata,November 24.

Cosmic dust and modeling, Department of Physics,Patna University, Patna, November 26.

Dark molecular clouds, Science with HCT workshop,IIA, Bangalore, January 21-22.

Commissioning of IUCAA 2 meter telescope and futureopportunities for universities, NSSS-2006 workshop,Waltair University, Vishakhapatnam February 11.

Effects of Earth’s atmosphere on astronomicalobservations and new generation telescopes, Workshopon Astronomy and Astrophysics, Department ofPhysics, Assam University, Silchar, February 21.

Earth’s atmosphere and new generation telescopes anddust models and interstellar medium, S.N. College,Purulia, February 23.

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Earth’s atmosphere and its effects on astronomicalobservations and modern telescope technologies andnew era, Space Meteorology workshop for IAF officers,Department of Atmospheric and Space Sciences,University of Pune, Mar 1-14.Application of artificial neural network to stellarspectra and TAUVEX data, TAUVEX Science Meeting,IIA, Bangalore, March 21-23.

Dust and its role in astrophysics, IPR, Ahmedabad , Mar27.

Priya Hasan

Computers and Astronomy, Refresher Course inAstronomy and Astrophysics, IUCAA, Pune, May 16.

Archival data and its potential, Refresher Course inAstronomy and Astrophysics, IUCAA, Pune, May 17.

AGN host galaxies: Observations and simulations,European Association for Research in AstronomyWorkshop, IAP, Paris, December .

Lives and death of stars, Introductory Workshop onAstronomy and Astrophysics, Osmania University,Hyderabad, February.

Ajit Kembhavi

Library consortia and UGC infonet, UGC InfonetProgramme, Government Medical College, Aurangabad,April 20.

Introduction to networks and astronomy researchfacilities in India and France, Workshop on Indo-FrenchAstronomy Network : Prospects and Programmes,IUCAA, Pune, June 30.

Galaxy formation : The AGN-spheroid connection,Workshop on Indo-French Astronomy Network :Prospects and Programmes, IUCAA, Pune, July 1.

Einstein’s gravity, Master Resource Persons TrainingProgramme on Year of Physics - 2005, Institute of Physics,Bhubaneswar, July 27.

Einstein’s gravity and black holes, National Seminar onAstronomy and Astrophysics, Christ College,Irinjalakuda, Kerala, August 6.

Einstein’s gravity and black holes, Workshop on ExcitingAstronomy : From Stars to the Universe, CalicutUniversity, Kerala, August 8.

Noise, sky brightness and observing limits, Workshopon Observing Projects and Small Telescopes, IUCAA,Pune, August 31.

From the special theory of relativity to the generaltheory, Fergusson College, Pune, September 8.

Supermassive black holes, Einstein Centennial Meeting,University of KwaZulu-Natal, Durban, September 26.

Gravity without gravity : Newton, Einstein and blackHoles, Students Physics Society, University of KwaZulu-Natal, Durban, September 29.

The black hole in our galaxy, Witts University,Johannesburg, October 3.

Supermassive black holes, UNISA, Pretoria, October 4.

Promotion of e-information resources, Seminar on theUsage Promotion of E-Information Resources, LeMeridian, Pune, November14.

Virtual Observatories, YAM 2005, IUCAA, Pune,November 29.

Galaxies - I, Introductory Workshop : Instruments andObservations, Karnatak University, Dharwad, December5.

Galaxies - II, Introductory Workshop : Instruments andObservations, Karnatak University, Dharwad, December5.

Virtual Observatories, B.V. Bhoomaraddi College ofEngg. and Tech., Hubli, December 5.

Black holes : From Newton to Einstein, UGC-DAEConsortium for Scientific Research, Indore, December 14.

Human r esource development for planetary explorationprogramme, ISRO HQ, Bangalore, December 16.

The sky is the limit, Workshop on Astrostatistics,Department of Statistics, Calcutta University, December21.

Virtual Observatory : Status and future, ScientificAdvisory Committee Meeting, IUCAA, Pune, January 3.

Virtual Observatories : A new data paradigm, IISc.,Bangalore, January 17.

Gravitational lenses (Two talks), Seminar on Gravityand Light, CUSAT, Kochi, January 30.

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Stars (Two talks), Workshop on Introductory Astronomyand Astrophysics, Purulia, February 24.

Virtual Observatories, IIT, Kharagpur, February 25.

Virtual Observatories, Invited talk at InternationalConference, LCWS Bangalore, T/DAQ Session, IISc.,Bangalore, March 11.

Ranjeev Misra

Time series Analysis of Astronomical Data, Workshopon Astrostatistics, Department of Statistics, ScienceCollege, Kolkata, December 21.

Observational evidence for black holes, Utkal University,Bhubhaneswar, February.

Observational evidence for black holes, Dalmia College,Rajgangpur, Orissa, February.

Radiative processes, (two lectures), VSP and RefresherCourse, IUCAA, Pune, June.

The non-linear time series analysis of GRS 1915+105,UofA, Amsterdam,August 9.

Radiative processes in astrophysics, DinabhandhuCollege, Kolkata, May.

Observational evidence for black holes, St. Xavier’sCollege, Kolkata, May.

Sanjit Mitra

Non-circular beam correction to the CMB power spectrumPoster presentation in the Conference on OpenQuestions in Cosmology: the First Billion Years, MPAGarching, August 22-26.

Surfing on gravitational waves , Plenary talk at the YoungAstronomers’ Meet, IUCAA-NCRA, Pune, November 30.

J. V. Narlikar

Science centres as tools for science education, a keynoteaddress delivered at the 4th Science World Congress,Rio de Janeiro, Brazil, April 12.

Scientific temper and cultural systems , 4th ScienceWorld Congress, Rio de Janeiro, Brazil, April 12.

Cosmology (2 lectures) VSP, IUCAA, Pune, May 26.

Einstein and our understanding of the universe, Mid-year meeting of the Indian Academy of Sciences,Bangalore, July 7.

A case for alternative cosmology, 9th Asian-PacificRegional Meeting of the International AstronomicalUnion, Bali, Indonesia, July 28.

Einstein and cosmology, 29th International CosmicRay Conference, (organized by the Tata Institute ofFundamental Research, Mumbai), Y.B. ChavanAuditorium, Pune, August 5.

Cosmology in the post-Einstein era, Physical ResearchLaboratory, Ahmedabad, August 10.

What is special relativity?, Sir Parshurambhau College,Pune, August 12.

Theory of relativity Department of Physics, Universityof Pune, Pune, August 19.

Cosmology, Fergusson College, Pune, September 12,

Gravitational collapse with negative energy fields (atechnical talk) SARS Einstein Centennial Meeting at theUniversity of Kwazulu-Natal, Durban, South Africa,September 25.

Theory of relativity (a general talk), SARS EinsteinCentennial Meeting at the University of Kwazulu-Natal,Durban, South Africa, September 26.

Theory of relativity - I and II (two lectures) Conferenceon Albert Einstein Theories and Present Scenario, Thane,November 18.

Facts and speculations in cosmology, Sikkim-ManipalInstitute of Technology, Sikkim, March 22.

Gravitational collapse with negative energy fields,Physics Department, North-Bengal University, Siliguri,March 24.

Gravitational collapse with negative energy fields,12th Regional Conference on Mathematical Physics,The National Centre for Physics, Islamabad, March 27.

T. Padmanabhan

Holographic aspects of Einstein gravity, UCTCosmology Meeting, Capetown, South Africa, July 7.

Dark energy and the cosmological constant,UCTCosmology Meeting, Capetown, South Africa, July 8.

Nonlinear gravitational clustering in expandinguniverse,UCT Cosmology Meeting, Capetown, SouthAfrica, July 9.

Dark energy- Mystery of the millenium, EinsteinConference, Paris, July 20.

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Observations and interpretation of dark energy in theuniverse, International Cosmic Ray Conference, Pune,August 5.

Challenges in the study of nonlinear gravitationalclustering, Workshop on Statistical Mechanics of Non-Extensive Systems, Paris, October 24.

A new perspective on gravity, Einstein’s Legacy in theNew Millennium, Puri, December 18.

Atoms of spacetime, (Abdus Salam Memorial lecture),Jamia Millia Islamia, New Delhi, February 28.

Dark energy, IISc, Bangalore, August 9.

Dark energy in the universe, KSCSTE, Trivandrum,August 17.

A holographic perspective of gravity, (HighlightColloquium), SISSA, Italy, November 8.

Horizons and/of Gravity, [TIFR Colloquium, Mumbai],November 22.

A new perspective on gravity, Harishchandra ResearchInstitute, Allahabad, April 26.

Origin of structure in the universe, School onCosmology and Very Early Universe, IUCAA, Pune,December 26.

A. N. Ramaprakash

Atmospheric effects in astronomy: Training school forInternational Astronomy Olympiad, Nehru ScienceCentre, Mumbai, May 17.

The world of large and small telescopes: Inauguralmeeting on Calicut University Observatory, CalicutUniversity, Kerala, August 8.

Laboratory and sky experiments training : RefresherCourse on Astronomy and Astrophysics, IUCAA, Pune,May 22.

Varun Sahni

Braneworld cosmology (Invited review), Dark EnergyMeeting, Ringberg Castle, Germany, February 26 - March1.

Dark energy (Invited review), School on Cosmologyand the Very Early Universe, IUCAA, Pune, December26-30.

The cosmological constant and dark energy (Plenarytalk), Physics in the trails of Einstein, Saha Institute ofNuclear Physics, Kolkata, November 21-22.

The cosmological constant — Einstein’s Enduringlegacy (Plenary talk) Physics 2005, 100 years afterEinstein’s Revolution, IIT Kanpur, November 3-6.

Dark energy (Plenary talk), Third 21COE Symposium :Astrophysics as Inter-disciplinary Science,WasedaUniversity, Tokyo, Japan, September 1-3.

The cosmological constant and the acceleratinguniverse, (Plenary talk) International Year of Physicscelebrations Bhabha Atomic Research Centre, Mumbai,India, July 22.

Tarun Souradeep

Statistical isotropy of CMB anisotropy, Planck GroupMeeting at JPL (Caltech), Pasadena, March 29.

Measuring statistical isotropy of CMB anisotropy,Fundamental Physics With Cosmic MicrowavemBackground Radiation, The Center for Cosmology,University of California, Irvine March 23-25.

Cosmology with CMB anisotropy, Plenary talk at theWHEPP-9, Bhubaneshwar, Januaary.

Status of CMB observations, A.K. RaychaudhuriMemorial School on Cosmology and the Very EarlyUniverse, IUCAA, PunDecember.

Statistics of CMB anisotropy, International workshopon ‘Astrostatistics’, Kolkata, India, December 23.

Cosmological quests in the CMB sky, plenary talk at theInternational meeting on Einstein’s Legacy in the newMillennium, Puri, December 15.

Two lectures on Introductory Cosmology, IUCAAsponsored Introductory Astronomy school, Dharwad,December 7.

CMB anisotropy at the frontiers of cosmologyColloquium at ARIES, Nainital, November 7.

Frontiers of cosmology with the CMB anisotropyColloquium at the Institute of Mathematical Science,Chennai, September 30.

Mining the CMB anisotropy for early universe physicsSeminar at the Institute of Mathematical Science, Chennai,September 29.

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Observable test of cosmological principle, PhysicsColloquium at the Indian Institute of Technology, Chennai,September 28.

Testing the statistical isotropy of CMB maps, MPA/ESO/ MPE/ USM Joint Astronomy Conference on ‘OpenQuestions in Cosmology’, Garching, Germany, August24.

Statistical isotropy of CMB anisotropy, COSMO 05: 9thInternational Workshop on Particle Physics and the EarlyUniverse, Bonn, Germany, August 28 - September 1.

Cosmological principle and the Cosmic microwaveBackground , Physics Colloquium at the Indian Instituteof Technology, Kanpur, April 4.

R. Srianand

Search for molecules with ELTs, Captown IAUSymposium on Science with Extremely Large Telescopes,September.

A review of IGM, IAU Symposium, South Africa,Capetown, Septmber.

K. Subramanian

The origin and evolution of cosmic magnetism, Reviewtalk, Cosmic Ray Propagation Meeting, Institute ofAstrophysics, Paris, France, November.

Magnetic fields and CMB anisotropies andPolarization, (Plenary review), International Conferenceon The Origin and Evolution of Cosmic Magnetism,Bologna, Italy, August.

CMBR anisotropies: Theory, School on Cosmology andvery Early Universe, IUCAA, Pune, December.

Structure formation (2 lectures), Cosmic magnetic fieldsIUCAA Refresher Course in Astronomy andAstrophysics and VSP, IUCAA, Pune, May-June.

Lecture Courses

Naresh Dadhich

General relativity, University of Kashmir, Srinagar,October 2005 (8 lectures).

Sanjeev Dhurandhar

Special and general relativity and their applications,Einstein Centenary Conference, S. P. College, Pune,December 8 - 10 (4 lectures).

Ranjan Gupta

Spectroscopy; Spectroscopy Instrumentation andApplications based on neural networks, IntroductoryWorkshop: Instruments and Observations, Departmentof Physics, Karnataka University, Dharwad duringDecember 5-7 (3 talks).

Earth’s Atmosphere; New generation telescopes;Artificial neural networks and applications to stellarspectroscopy; Interstellar dust models at Department ofPhysics, Kumaon University, Nainital February 28 toMarch 2 (6 talks).

Ajit Kembhavi

The physics of stars, Refresher Course, Department ofPhysics, Utkal University, Bhubaneswar, November 7 - 9(4 talks).

Galaxies in the universe, Certificate Course inAstronomy and Astrophysics, University of Mumbai,February 26 (3 talks).

J. V. Narlikar

Cosmology from the sidelines , Junior ResearchScholars, IUCAA, Pune, May 10, 11, 12 (3 lectures).

T. Padmanabhan

Aspects of gravitation, Cochin University, August 11- 14 (8 letures).

Making sense out of the universe, X Special Courses atObservatorio Nacional/Brazil National Observatory at Riode Janeiro, September 26-30 (5 lectures).

Introductory Astronomy and Astrophysics ,Order ofmagnitude, IUCAA, Pune, May 16-19 (3 lectures).

R. Srianand

UV spectroscopy of AGNs, Udaipur University, PhysicsDepartment, Astrosat workshop on AGNs (3 lectures).

Diffuse matter in space, VSP, IUCAA, Pune, May-June (5lectures).

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Vacation Students’ Progra m m e

Participants and Lecturers of the Vacation Students’ Programme

The Vacation Students’ Programme (VSP) for students intheir penultimate year of their M.Sc. (Physics) orEngineering degree course was held during May 16 - July1, 2005. Eleven students participated in this programme.The participants attended about 50 lectures dealing with

School Students’ Summer Programme - 2005

The annual IUCAA School Students’ Summer Programmewas held from April 18 to May 27, 2005. This programmeat IUCAA was started in 1993 for the school students ofPune. It gives a glimpse of the pursuit of scientificresearch to the young minds and has been conducted forsix weeks. Each week, starting on Monday, a fresh batchof 26 students of class VIII and IX were invited to workon a project at IUCAA. Groups of four to six studentswere attached to a scientist at IUCAA, who guide themon scientific projects. In the spirit of true research, thestudents and guides work together unfettered by a setsyllabus or course guidelines, time schedules. Thestudents are given access to the IUCAA library. On thelast day of every batch, the student teams present thework they did during the week and submit a report. This

wide variety of topics in Astronomy and Astrophysics,given by the members of NCRA and IUCAA. They alsodid a project with one of the faculty members of IUCAAduring this period. K. Subramanian was the facultycoordinator of this programme.

year the students carried out projects under thesupervision of Susmita Chakravorty, Hum Chand, V.Chellathurai, Sanjeev Dhurandhar, Sunu Engineer, ArvindGupta, Ranjan Gupta, Priya Hasan, Kanti Jotania, GaurangY. Mahajan, Vidula Maiskar, Jayant Narlikar, ArvindParanjpye, Vijay Mohan, Manoj Puravankara, AshokRupner, Saumyadip Samui, Tarun Souradeep andKandaswamy Subramanian. The projects were diverse,covering wide ranging topics. Some students estimatedthe latitudes of various places seeing the IUCAA Foucaultpendulum and by observing shadow of gnomon andlearned to use trigonometry to measure heights. Whileothers studied the properties of electromagnetism,Kepler’s laws and our planets, planets in extra-solarsystems, the galaxy, the universe, refraction, fractals, bio-

Students in various activities during the School Students' Summer Programme

(VIII) SCIENTIFIC MEETINGS AND OTHER EVENTS

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technology, genetic engineering and genetically modifiedfoods, HIV virus, human anatomy — skeletal and digestivesystem, . They also constructed solar system models,models of the Cassini probe, kaleidoscope, periscopesand scientific toys. Besides the team project, the studentsalso had time for joint activities, such as, making scientifictoys from scrap, exploring the the IUCAA Science Park,observing sunspots and viewing popular science movies.A new item this year were informal interactive sessionswith young, budding scientists, Abhishek Rawat, ArmanShafieloo, Ujjaini Alam, Sanjit Mitra who are workingtowards their Ph.D. in IUCAA and IUCAA VisitingAssociate Pavan Chakraborty. Besides answeringquestions, the young scientists shared their experiences

Refresher Course in Astronomy and Astrophysics forCollege and University Teachers

The Refresher Course in Astronomy and Astro-physics for college and university teachers was heldduring the period May 16 - June 17, 2005. Partici-pants were selected from all over India and eigh-teen highly interested participants took part in thecourse. The faculty, post-doctoral fellows and stu-dents joined in the programme with great enthu-siasm. The scientific and the administrative staffwere of vital help in ensuring that the course ransmoothly. The lecture courses were designed bySanjeev Dhurandhar ,and KandaswamySubramanian, who was the coordinator of the Va-cation Students’ Programme (VSP). The coursefirstly, consisted of introductory lectures, which cov-ered the basics of astronomy and astrophysicsand secondly, of lectures providing overviews ofdifferent aspects of astronomy. A few lectures werearranged on advanced topics. There were speciallectures by experts from outside Pune on frontierareas related to astronomy and astrophysics and

Participants and Lecturers of the Refresher Course in Astronomy and Astrophysics

and the joy of doing research in science. This year thestudents could use the facilities of the MuktanganVidnayan Shodhika — IUCAA’s new scienceexploratarium in the Pulastya building , and also benefitedfrom a collaborative effort with the Centre for Researchin Cognitive System, NIIT Ltd., New Delhi, who kindlysent us Computer Aided Science experience - CAXkits consisting of experiments in electricity, heat andsound. The kits allowed the students to perform (real, notsimulated) science experiments first and then study thetheory behind every experiment, in contrast to what isnormally done in schools, where theory is done first andthen a few experiments are performed.

which described the various frontline scientificprojects in which India is taking part. The lecturerswere from ISRO Satellite Centre, Bangalore. In-dian Institute of Astrophysics, Bangalore, and theTata Institute of Fundamental Research, Mumbai.Laboratory sessions were an important componentof the course; this was in order to concretise ideasand concepts in basic astronomy. A scientific visitto the IUCAA’s 2 metre optical telescope at Giravaliand to the Giant Metre Radio Telescope atNarayangoan was arranged on June 13, 2005 forthe participants of the refresher course and theVSP. Finally lectures and useful reference ma-terial were copied on CDs, which were distributedto each of the participants. It was clear that at theend of the course, the participants benefited sub-stantially and were inspired to take up researchand teaching in astronomy and astrophysics at theirhome institutions. Sanjeev Dhurandhar was the co-ordinator of this course.

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W orkshop on Observing Projects with Small Telescopes

Twenty eight participants from various universities andcolleges attended the workshop. The workshop themewas to discuss projects and exercises for M.Sc. studentshaving course work in astronomy. Both types of projectswhich can be undertaken with small telescopes as well aswithout telescopes were discussed. Basic tools neces-sary for implementing such projects viz. telescopes, de-tectors, image processing, photometry, spectroscopy anderror analysis, were covered by the lecturers. Speakersand topics were as follows:

Ajit Kembhavi (IUCAA) on Noise, Sky Brightness andObserving Limits; Ranjan Gupta (IUCAA) on Spectros-

Participants and lecturers of the workshop on Observing Projects with Small Telescopes

An Introductory Workshop: From Stars to the Universe

The 14 inch telescope at the Madhava Observatory

An introductory workshop titled From Stars to theUniverse was organized by IUCAA in collaboration withthe Physics Department, University of Calicut, Kozhikode,on the university campus on August 7 and 8, 2005. Theworkshop was attended by about 150 students and

copy; S.K. Pandey (Pt. Ravishankar Shukla University,Raipur) on Projects and Exercises in Astronomy; ArvindParanjpye (IUCAA) on Using an Astronomical Telescope;Vijay Mohan (IUCAA) on Image Processing and Pho-tometry; and Abraham Samson (IIA, Bangalore) on Domesfor Small Telescopes.

Participants also presented the facilities in their depart-ments and observing projects being undertaken by them.A demo session was held on Image Processing usingIRAF. S.K. Pandey and Vijay Mohan coordinated theworkshop, and was conducted during August 29-31, 2005.

teachers from university departments and colleges aroundKozhikode. The lectures given at the workshop were asfollows :

G. Ambika (Maharaja’s College) : Non linear dynamics

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International Conference onEinstein's Legacy in the New Millennium, Puri

Participants of the International Conferenceon Einstein's Legacy in the New Millennium

and Astrophysics; Naresh Dadhich (IUCAA) : Introductionto Einstein’s Theory; Ajit Kembhavi (IUCAA) : (i) Einstein’sGravity (ii) Opportunities in Astronomy; V.C. Kuriakose(Cochin University) : Elements of Cosmology; JayantMurthy (IIA, Bangalore) : Diffused UV Observations; NinanSajeeth Philip (St. Thomas College) : Neural Networks andTheir Applications in Astronomy; A. N. Ramaprakash(IUCAA) : The Use of Small and Medium Telescopes; N.Kameswara Rao (IIA, Bangalore) : Astronomy with MediumSized Telescopes; Ulysses John Sofia (WhitmanAstronomy, USA) : Interstellar Grains and Dust.

There was a discussion session on Opportunities inAstronomy led by Ajit Kembhavi. The lectures were allfollowed by intensive questions and answers, anddiscussion on the topics covered.

The international conference titled Einstein’s Legacy inthe New Millennium was co-organised by IUCAA, UtkalUniversity and Institute of Physics, Bhubaneswar, atToshali Sands, Puri, during December 15 – 22, 2005. Thisconference was co-sponsored by IAGRG, HRI (Allahabad),IMSc. (Chennai), RRI (Bangalore), SINP (Kolkata), andTIFR (Mumbai) and financial support was also receivedfrom DAE-BRNS, DST, and ISRO. The aim of the conferencewas to bring together people working in different areas ofquantum gravity, and bring fruitful interactions amongstthem. The plenary talks were delivered by Martin Bojowald,Atish Dabholkar, J. Ehlers, G. Gibbons, Rajesh Gopakumar,G. ‘t Hooft, Romesh Kaul, Swapna Mahapatra, H. Nicolai,Peter Van Nieuwenhuizen, T. Padmanabhan, Jogesh Pati,J. Pullin, Ashoke Sen, Parampreet Singh, Tarun Souradeep,Sandip Trivedi, W. Unruh, M. Varadarajan and B. de Wit.

A special event which took place during the workshopwas the inauguration of the Madhava Observatory byNaresh Dadhich, Director, IUCAA, which has a new 14”telescope to be used by students and faculty of theuniversity. The well equipped observatory with a domehas been set up with technical assistance from the IndianInstitute of Astrophysics (IIA), Bangalore, with domedesign and construction being supervised by J.P.Abraham Samson of IIA. During the workshop, therewas a discussion between Syed Iqbal Hasnain, ViceChancellor of the university, his senior colleagues, andvisitors from IUCAA about possible continuingcollaborative programmes to be undertaken over the nextfew years. The coordinators of the workshop were B.Ravishankar Babu from the University of Calicut andAjit Kembhavi from IUCAA.

In addition to the plenary talks, the conference devotedthree evenings for focused discussion on String Theory,Loop Quantum Gravity, and Cosmology, andcoordinated by Debashis Ghoshal, Martin Bojowald andVarun Sahni respectively.

G. ‘t Hooft delivered a special colloquium, which wasattended by the students from the Utkal University aswell. The conference was quite successful in providinga forum for very stimulating discussions and allowingfree exchange of different points of view. The scientificorganization of the conference was handled by acommittee co-chaired by T. Padmanabhan (IUCAA) andJ. Maharana (IOP), and the local organization wascarried out by a committee chaired by L.P. Singh ofUtkal University.

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Introductory Workshop: Instruments and Observations

Participants of the Introductory Workshop: Instruments and Observations

An Introductory Workshop: Instruments andObservations was organized by the Department ofPhysics, Karnataka University, Dharwad, during December5-7, 2005. The workshop was sponsored by IUCAA, Pune,with additional support from Karnataka University underunassigned UGC grant. The workshop was inauguratedby Ajit Kembhavi, IUCAA with M.I. Savadatti, formerVice-Chancellor of Mangalore University, speaking onthe occasion. The aim of the workshop was to acquaintthe teachers with the basics of Astronomy andAstrophysics, which will be helpful for teaching/introducing the topics at undergraduate and postgraduatelevel, to provide an opportunity for the teachers fromcolleges and universities to undertake research activities,and mainly to learn the latest developments in the areas.

The workshop was attended by 38 teachers fromuniversity departments and colleges from Karnataka andneighbouring states. A few students and all the research

students of the department also participated actively inthe workshop. The resource persons spoke as follows:

Ajit Kembhavi (IUCAA): Galaxies (2 lectures); RanjanGupta (IUCAA): Spectroscopy, SpectroscopyInstrumentations Applications: Based on NeuralNetwork; Vijay Mohan (IUCAA) : Optical Telescopes,Detectors and Image Processing; Tarun Souradeep(IUCAA): Introduction to Cosmology (2 lectures); B.A.Kagali (Bangalore University) : Telescopes and theirCharacteristics; S.C. Chakravarty (Department of Space,ISRO, Bangalore): ISRO’s Space Science and AstronomyMissions.

Uday S.Raikar from the Department of Physics, KarnatkaUniversity and Ranjan Gupta from IUCAA, were thecoordinators of the workshop, with B.G. Mulimani asChairman of the Workshop Organising Committee.

Workshop on Astrostatistics

The Worskhop on Astrostatistics was jointly organizedby the Inter-University Centre for Astronomy andAstrophysics, Pune, and Department of Statistics,Calcutta University, during December 21-23, 2005. Theworkshop was inaugurated by Asis Kumar Banerjee, ViceChancellor, Calcutta University on December 21, 2005.

Speakers and topics of the different technical sessionswere as follows: S.P. Mukherjee ( Calcutta University) :

Statistics for astronomy- An overview; G.J.Babu ( PennState University) : Statistical problems in astronomyand resampling techniques; Ajit Kembhavi (IUCAA):Sky is the limit; Kalyan Das (Calcutta University) :Exploratory data analysis; Somnath Bharadwaj (IITKharagpur) : Galaxy redshift surveys; Ranjeev Misra(IUCAA): Time series analysis of astronomical data;Asis Kumar Chattopadhyay (Calcutta University) :Statistical inference and missing data analysis; Sugata

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An Introductory Workshop: Sun and Stars

The participants of the Introductory Workshop: Sun and Stars

An Introductory Workshop: Sun and Stars was orga-nized by IUCAA in collaboration with the Department ofAstrophysics, St. Xavier’s College, Kolkata during No-vember 21 -23, 2005. A total of 87 participants from differ-ent university departments and colleges attended theworkshop, out of which twenty candidates were from otherparts of India. The lectures given at the workshop were asfollows:

Jagdev Singh (IIA, Bangalore): Instruments andtechniques to observe the Sun and structure anddynamics of the Sun; Sandip K. Chakrabarti (SNBNCBSand Centre for Space Physics) : Astrophysical flowsabout black holes and neutron stars; Ashoke K. Sen(Assam University): Fundamentals of astronomy andphotometry and polarimetry with small telescope; RanjanGupta (IUCAA): Earth’s atmosphere, telescopes andeffects and astronomical spectroscopy; NarayanBanerjee (Jadavpur University): The new turn incosmology; Partha Sarathi Joarder (Indian Statistical

Institute, Kolkata): A short introduction to solarmagnetohydrodynamics; Debiprosad Duari (M.P. BirlaPlanetarium): Astrophysics and cosmology — Currentperspectives and future challenges (Part A) andAstrophysics and cosmology — Current perspectivesand future challenges (Part B); Kamales Kar (SahaInstitute of Nuclear Physics, Kolkata): The theory of typeII supernova explosions; Biswajit Basu (AAVSO and SkyWatchers’ Association): The effect of solar flares on theVLF radiowave propagation and ionosphericdisturbances. Jagdev Singh delivered one eveningpopular level talk on Expedition to Antarctica region tostudy the Sun. All the participants were taken to the St.Xavier’s College Observatory, which was established inthe year 1860 and is at present under renovation processsince November 2004. Biswajit Basu also demonstrated aVLF receiver at the observatory for 2 days, showing theionospheric effects including sunrise and sunset events,etc.

Sen Roy (Calcutta University) : Some aspects ofmultivariate analysis; Ashish Mahabal (Caltech) :Clustering, classification and the search for outlier; P. K.Sen (North Carolina State University) : Some stochasticperspectives in astrostatistics; Tarun Souradeep(IUCAA): Statistics of the cosmic microwave backgroundsky; Manisha Pal (Calcutta University): Descriptivestatistics; Tanuka Chattopadhyay (S.D.B. College,Howrah) : Some case studies; Sajeeth Philip (St. ThomasCollege, Kozhencherry): Bayesian statistics for artificialneural network design; U.C.Joshi (PRL, Ahmedabad):Probing the inner region of the milky way; and MalayGhosh (University of Florida): Bayesian methods.

Besides the above technical lectures, there was a speciallecture on December 22, 2005 by J.K.Bhattacharya ofIndian Institute for Cultivation of Science, Kolkata onthe topic “Bose Einstein statistics and condensationphenomena.”

About sixty participants from different universities,colleges, institutes and from different parts of the countryattended the workshop.

Asis Kumar Chattopadhyay of Department of Statistics,Calcutta University and Ajit Kembhavi of IUCAA, Punewere the joint coordinators of the workshop.

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Young Astronomers' Meet 2005

The participants of the Young Astronomers’ Meet

The 9th Young Astronomers’ Meet (YAM) was held inIUCAA and NCRA during November 29 - December 2,2005. YAM serves as a unique forum for researchstudents working in Astronomy and Astrophysics in thecountry, by providing them a unique opportunity topresent their work and interact with like-minded fellow-researchers. YAM was initiated in 1992 and the first onewas held in NCRA. YAM 2005 was co-sponsored byDST, IUCAA and NCRA, and the organisation washandled by the graduate students of the latter twoinstitutions under the guidance of A. N. Ramaprakash.

The schedule included technical talks and posterpresentations by participants covering most of the areasin A & A, as well as three special evening colloquia, byA. K. Kembhavi (Virtual Observatories), T. Padmanabhan(Dark Energy) and R. Nityananda (The Graver Side ofLight). On the last day, a trip to GMRT and the IUCAAtelescope at Girawali was arranged. The meet wasattended by 81 students from various institutions acrossthe country. In all, 35 talks and 9 posters were presented.Students from Pt. Ravishankar Shukla University, Raipur,have proposed to hold the next YAM.

Taking advantage of the presence of some of the distin-guished speakers at the International conference onEinstein's Legacy in the New Millennium, held at Puri, asatellite school on Cosmology and Very Early Universewas organized at IUCAA during December 26-30, 2005. Itwas felt that the activity in both strings and loop quan-tum gravity is coming up to a stage for applications incosmology and one could expose young researchers inthe country to this exciting and emerging area of research.This was the main motivation for the school, which wasscientifically directed by Abhay Ashtekar.

It began with the lectures on cosmology (by JuergenEhlers, T Padmanabhan, Varun Sahni, K Subramaniam and

School on Cosmology and VSchool on Cosmology and VSchool on Cosmology and VSchool on Cosmology and VSchool on Cosmology and Very Early Universeery Early Universeery Early Universeery Early Universeery Early Universe

Tarun Souradeep), which defined the cosmological con-text and setting. It was then followed by lectures on stringtheory (by Sunil Mukhi, Jnan Maharana, Atish Dabholkarand Sandip Trivedi) and loop quantum gravity/cosmol-ogy (by Abhay Ashtekar, Martin Bojowald, ParampreetSingh, Shyam Date and Golam Hossain). There were about30 participants from various institutes and universities.

It was a very intense and focused engagement which wasrounded up by a panel discussion on the emerging can-vas of synergy between quantum gravity theories andcosmology. This school was dedicated to the memory ofA. K. Raychaudhuri, and coordinated by Naresh Dadhich.

The participants of the School on Cosmology and very Early Universe

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Cosmology for Everyone : Lecture series

Mark Whittle delivering a lecture

Mark Whittle, (University of Virginia, USA), who wasvisiting IUCAA, gave a series of four informal eveninglectures at Muktangan Vidnayan Shodhika, the ScienceExploratorium from January 4 to 7, 2006.

The lecture titles were: Evidence for the hot big bang,Witnessing the sound and flash of big bang, and

Assembly of the cosmic structure - from stars to galaxiesto the tapestry. These talks were attended by about 15amateur astronomers and visitors to IUCAA. Eventhough the talks were meant to be for ‘every one’ it turnedout that those attended the talks had more deeper interestin the subject and Mark, who had planned only threetalks, delivered one more talk!

W orkshop on Telescope Making

Arvind Paranjpye conducted a workshop on telescopemaking at Bipin Bihari College, Jhansi, during January 27- 28 , 2006. In this workshop, ten teams from differentschools and colleges participated. The telescopes wereof refracting type with 42 mm f /10 achromatic lens. Themount for these telescopes were made using PVC pipesand pipe joints.

There were lectures on history and types of telescope.The participants estimated the focal lengths of the lens

Participants of the Workshop on Telescope Making

by focusing on the Sun. In the night, actual observationswere carried out. Next day, the participants were shownhow to image the sun on a sheet of paper for the purposeof seeing the sunspots and solar eclipse. A session ontelescope maintenance and a question/answer wasconducted. Sunanda Kirtane and Chandrakant Gandhiwere the local organizers of the workshop.

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Public Outreach Programmes

IUCAA has active Public Outreach Programmes whoseprimary aim is to inculcate scientific interest among schoolstudents (especially underprivileged ones), encourageand help talented children to do scientific projects,promote amateur astronomy and inform the generalpublic about the importance and excitement of recentscientific achievements, especially in astrophysics. Toachieve these goals, several programmes were undertakenlast year. While some of these programmes are held allthrough the year, others were organised during thesummer vacation. Apart from these regular programmes,the National Science Day and IUCAA Open Day werecelebrated on February 25 and 28, 2006. These PublicOutreach Programmes, are housed in the MuktanganVidnyan Shodhika.

Activities for school students

Second Saturday Lecture and DemonstrationProgramme

School students from class IX and X were invited fromPune, to attend Lecture and Demonstration Programme,held on the second Saturdays of the month. Theselectures, which were given in English and in Hindi/Marathi, aimed to inspire the students by informing themof recent developments in Science.

Science Activity Workshop

These workshops were conducted on every Monday,Wednesday, and Friday and each session was attendedby about fifty school students from class fourth to tenth.The students were shown how to make and appreciateseveral scientific toys, which were made of simple andeasily available materials like matchsticks, cycle valvetube, old cycle tube, film cans, old newspapers, ball penrefills, etc. Some of these toys made by the studentswere, magnetically elevated pencils, a simple electricmotor, newspaper caps, Sudarshan Chakra, balloonpump, matchstick mecanno, etc.. The aim of theseworkshops is to show students that science is fun andexciting. The low cost and easy availability of the materialsused, allows the students to be free, leading to maximumparticipation in their part. This programme is especiallybeneficial to under privileged student who may not haveaccess to costly scientific apparatus. FMEPL, a mediagroup produced a short documentary film (12-minute)on this program titled “TRUTH AND JOY OF SCIENCE”which captures the inquisitive mood of the studentsduring the workshop. This TV programme was telecastedon Doordarshan .

Advanced Projects

Interested school and college students undertakescientific projects at IUCAA, which may be a part oftheir curriculum.

Bakul Purohit, Prachee Bahulekar, and Solnali Deshmukh,students of Cummins College of Engineering for Women,Pune, did a project on making a Celeostat, as a part oftheir engineering project. Their project was rated high intheir graduate examinations held by the Pune University.The Celeostat has been installed on the terrace ofMuktangan Vidnyan Shodhika

Sonal R. Kasar, Jyoti P.Pagar, Vrishali A.Bagul, ShaktiN.Bajaj, Jyoti R.Nikam, and Yogita P. Gangurde, B.Sc.students of the K.R.T. Arts, B.H. Commerce and A.M.Science College, Nashik, visited IUCAA for a period ofsix days to do project on study of solar limb darkening.During this period, they took photometric observationsand reduced their data. They observed the sun inJohnson B,V, R, I passband.

Such projects done in previous years have received manynational and international recognition.

Hamsa Padmanabhan, XI standard student of theKendriya Vidyalaya, Ganeshkhind Road, Pune, had donea detailed project on a toy, in which a pen is suspended(and it also spins) in air due to magnetic forces. Her paperbased on this project won three awards at the IntelInternational. She bagged the 2nd prize in physics atISEF, first prize in Physics from United TechnologiesCorporation for excellence in the science and engineeringcategory, and American physics teachers and theAmerican Association for physics society jointlyawarded her the third prize.

Madhura Gokhale, Department of Physics, University ofPune, and Onkar Dixit, a standard XII student ofFergusson College were invited to participate in theamateur section of 9th Asia Pacific Regional IAU(International Astronomical Union) Meeting, at Bali,Indonesia, in July 2005 for their project on the study ofcomet Machholz. Unfortunately, both of them could notparticipate in the meeting, as they were stranded atMumbai Airport due to unprecedented rains.

Workshops and Lecture Series

To mark the “Year of Physics”, two workshops wereheld in collaboration with NCERT and PhysicsDepartment of Pune University, for 100 muncipal schoolstudents during November 29-30, 2005.

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IUCAA organizes visits to the campus, for interestedpeople from different professional backgrounds and agegroups. These visits, which are by pre-arranged invitationonly, take place typically on Thursdays. On each visit,about 35 visitors were given a brief introduction aboutIUCAA and were shown the various exhibits on thepremises and the science park. Student visitors with moretechnical background were also shown theinstrumentation laboratory.

Contribution to Newspapers/Articles

Muktangan Vidnyan Shodhika members have beencontributing weekly science features to a local newspaper“The Maharashtra Herald”. These articles explain somescientific principles and describe “Do-it-yourself”experiments which young readers can perform. Twenty-three features (12 plus 11) have been published on Fridays(for high schools students) and Saturdays (for secondaryschools students) from January 2006 onwards.

National Science Day

The National Science Day was celebrated at IUCAA onFebruary 25th and on February 28th. On Saturday,February 25th science related competitions were held forschools students. The centre was opened to the generalpublic on February 28th, so that they may acquaintthemselves with the research done at IUCAA andappreciate scientific temper and methodology.

Inter-School Competitions

Schools in Pune region were invited to participate in theinter-school science competitions. On February 25th fivestudents each, from 80 schools took part in the quiz,essay and drawing competitions organised at IUCAA.

Topics for the drawing and essay competitions weresuitably chosen to enable the students to exhibit theirfertile imagination and scientific knowledge. Based on apreliminary written quiz held in the morning, three memberteams from five schools took part in the final quiz contest.The students were tested for their scientific andtechnology knowledge and their ability to solve puzzles.Films “Truth and Joy of Science” and on the life andworks of two great Indian cosmologists, Professor A. K.Raychaudhuri and Professor P.C. Vaidya (produced byVigyan Prasar, New Delhi) were screened for the studentsand teachers. Winners of the competitions were taken tothe IUCAA Girawali Observatory. During the two hoursstay at the Observatory, the students acquaintedthemselves with the telescope and its operation.

The Open House for Public

A large number of people from all age groups anddifferent walks of life visited IUCAA on February 28,2006.

Inauguration of “Science Attitude Promotion Van” ofMaharashtra Andhashradha Nirmoolan Samiti (M-ANiS)by Naresh Dadhich, marked the start of Open Day. M-ANiS, had set a poster exhibition and an expositiondemonstration of “Science Behind Miracles”.

The visitors viewed several posters describing thebasics of Astronomy and Astrophysics and thefundamental research done at IUCAA and interactedwith IUCAA members who demystified the technicaldetails of the research activities. Senior scientistsdirectly interacted with the visitors to clarify their doubtsabout astronomy and physics. A public talk, whichexplained the importance of this year’s Nobel prize inphysics, in non-technical language, was presented inthe evening.

Short interactive lectures on different topics were held.A scaled model of IUCAA Girawali Observatory, ademonstration of the seeing affect and telescope domeoperation were on display. Brownian motion and radiotelescope demonstrations were conducted by studentsof Fergusson College, Pune.

Visitors were encouraged to get hands on experience ofusing do-it-yourself experiments set up in theMuktangan Vidnyan Shodhika. Students ofAksharnandan school volunteered to give thedemonstrations. Films “Truth and Joy of Science” andon the life and works of Professor A. K. Raychaudhuriand Professor P. C. Vaidya were also screened.

Members of the Sky Watchers Association of Puneparticipated in explaining exhibits in the science parkand later on carried out sky observing programme forgeneral public.

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Winners of the Drawing, Essay and Quiz Competitions

Drawing CompetitionFirst prizeAkshay Hargude, New English School, Raman BaugNo second prize was awarded

Essay Competition MarathiFirst PrizeDeepti Dilip Patil, Mahialshram High SchoolSecond PrizeBhakthraj Thombre, Shri Fattechand Jain Vidyalay

Essay Competition EnglishFirst PrizeKshitij Gautam, Army School, KirkeeNo Second Prize was awarded

Science Quiz CompetitionFirst Prize:Team: Muktangan English School & Jr. CollegeSaurabh Rajendra GandhiShantanu Rajendra BhateNinad Hemant Watve

Second Prize:Team: S. P. M. English SchoolAmeya KarambelkarAniket PanseDevdnya Deshpande

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Popular Talks and Articles by theIUCAA Faculty

(a) Popular Talks

Naresh Dadhich

Science and Society (a Popular Science talk deliveredat the Master’s Resource Training Programme organizedby Rashtriya Vigyan Evam Prodyogiki Sanchar Parishadat Mumbai,) June 29.

Science and Society (a Public Lecture delivered at theMaster’s Resource Training Programme organized byRashtriya Vigyan Evam Prodyogiki Sanchar Parishad atBangalore,) July 13.

Science and Society (a Public Lecture delivered at theUniversity of Cape Town, South Africa,) September 24.

Science and Society (a Popular Lecture delivered atthe University of Srinagar, Jammu and Kashmir,) October17.

Sanjeev Dhurandhar

The Search for Gravitational Waves, Fergusson College,Pune, September 12.

Ajit Kembhavi

Virtual Observatory, Tilak Smarak Mandir, Pune, May 5.

Albert Einstein : 1905 - The Miracle Year, Institute ofPhysics, Bhubaneswar, July 27.

Einstein and Atoms, Inauguration of book“Tarankanchya Vishwat” Mahalaxmi Sabhagriha, Parvati,Pune, September 4.

Nobel Prize in Physics - 2005, National Science Day,IUCAA, February 28.

Albert Einstein : Some simple truths, School StudentsLecture Demonstration Programme, IUCAA, Pune,August 13.

Albert Einstein : Kahi Sadhi Satye (Marathi), SchoolStudents Lecture Demonstration Programme, IUCAA,Pune, August 13.

Albert Einstein : Some simple truths, Conference onEinstein’s Theories and Present Scenario, B.N. BandodkarCollege of Science, Thane, November 19.

Black holes : From Newton to Einstein, EDUSATNetwork, Consortium for Educational Communication,New Delhi, December 30.

Gravity and light, Assam University, Silchar, February21.

Sucheta Koshti

Ripples in Spacetime,National Science Day, IUCAA,February 28.

J. V. Narlikar

Revolutions in physics (TRDDC Distinguished Lecturedelivered at the Tata Research Development and DesignCentre, Pune,) June 10.

Revolutions in physics, a public lecture delivered atthe Institute of Mathematical Sciences, Chennai, July 1.

The amazing world of astronomy, Vikram SarabhaiMemorial Lecture delivered at the AhmedabadManagement Association, Ahmedabad, July 14.

Searches for extraterrestrial intelligence, a lecturedelivered at the Kishinchand Chellaram College, Mumbai,July 15.

Learning to live with science and technology, LalitDoshi Memorial Lecture organized by the LalitDoshi Memorial Foundation, Mumbai, August 4.

Paragrahavaril Jeevshrusti (Extra-terrestrial life) (inMarathi), a lecture delivered at the YashwantraoChavan Sahakar Sabhagruha, Ahmednagar, organizedby the Bhaskaracharya Astronomy Research Centre,Ahmednagar, August 16.

IUCAA’s architecture from an astronomer’s viewpoint,a lecture delivered at the National Film Archives, Puneorganized by the Forum for Exchange and Excellence inDesign, Pune, August 27.

School education : Some thoughts and reminiscences,V.G. Kulkarni Memorial Lecture delivered at the HomiBhabha Centre for Science Education, Mumbai,September 3.

Pruthvibaheril jeevshrushticha shodh (Search forextra- terrestrial life) (in Marathi), a lecture delivered atthe Second Saturday Lecture Series at IUCAA, Pune,September 10.

History and science, a lecture delivered at theDepartment of History, Nowrosjee Wadia College, Pune,September 16.

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Einstein and cosmology, a lecture delivered at theNehru Planetarium, Mumbai, September 21.

Life in the universe, a lecture delivered at the SpicerMemorial College, Pune, October 11.

Theory of relativity, a lecture delivered at the TamilNadu Science and Technology Centre, Chennai, October14.

Sapakshatecha Siddhanth (Theory of relativity) (inMarathi), a lecture delivered at the Shivaji University,Kolhapur, October 19.

Pruthvibaheril jeevshrushti (Extraterrestrial life) (inMarathi), a lecture delivered during the Conference on‘Albert Einstein Theories and Present Scenario’ atThane, November 17.

Searches for extraterrestrial life, a lecture delivered atthe Indian Community Centre, Sunnyvale : FOWL(Friends on Same Wave Length) (68th Meeting,) January9.

Modern cosmology from a historical perspective,Second Hasi Majumdar Memorial Oration Lecturedelivered at the Calcutta University, Kolkata, March 17.

Searches for extraterrestrial life, a lecture delivered atthe Tathyakendra (Dinabandhu Mancha), Siliguriorganized by the Paschimbanga Vigyan Mancha, Siliguri,March 23.

T. Padmanabhan

Cosmology, Kendriya Vidyalaya, Ganeshkhind, Pune,April 16.

Understanding our Universe, Homi Bhabha Centre forScience Education, Mumbai, June.

Our universe, Cochin University, August 12.

The darker side of the universe, U.C. College, Alwaye,Cochin, August 16.

The darker side of the universe, S.D. College , Alapuzha,Cochin, August 16.

The darker side of the universe, S.N. College, Kollam,Cochin, August 16.

Dark energy, Nehru Planetarium, Mumbai, November 21.

Dark energy, YAM, Pune, November 30.

Dark energy- The mystery of the millenium, INSA, Delhi,February 28.

Cosmo-genesis, Cafe Scientifique, British Council,Mumbai, March 8.

Dark energy, Cosmological conundrum, ChennaiMathematical Institute, January 16.

K. Subramanian

Traveling through time, Lecture in Astronomy School,QUANTA 2005, City Montessori School, Lucknow,November.

The expanding universe, Lecture in Astronomy School,QUANTA 2005, City Montessori School, Lucknow,November.

(b) Popular Articles

Naresh Dadhich

Amal Kumar Raychaudhuri (1923-2005), Current Science,89, 3, 569.

Jayant Narlikar - All rounder par excellence,Maharashtra Herald, October 29.

A lighthouse falls : Tribute to A.K. Raychaudhury,Physics Education, 22, 3, 219.

Einstein’s audacity, V. Vidyanagar (2006), page 18.

Beacon of light, Maharashtra Herald, April 13.

J. V. Narlikar

Eclipse of reason, The Times of India, June 4.

Reaching for the stars, The Times of India, July 30.

Challenges and benefits of studying astronomy,Souvenir, 65.

Yehi hai right size, baby, The Times of India, October15.

When exciting science is done in colleges, not in labs,Indian Express, October 22.

Hermann Bondi (1919-2005), Current Science, 89, 10,1767.

Origin (?) of the universe : Part-2, The expandinguniverse, Resonance, December.

The science-society interaction, Swasti, 3, 18.

Tools for science education, People Science Education

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Abstracts, 85.

The scientific temper: Indispensable to enlightenedcitizenship, Prabhuddha Bharata, January.

Science as an aid towards value education, Philosophyand Science of Value Education in the Context of ModernIndia, 147.

Kaise bane Oxford, Cambridge ki takkar ke sansthan(in Hindi) [How can we build institutions like Oxford andCambridge], Dainik Bhaskar, July 20.

Badalti duniya mein Hindustan (in Hindi) [The role ofIndia in a changing world], Rachana, January-April, 3.

Khatare ki aahat (in Hindi) [Signs of danger], (Aha!Zindagi, September) (Expressed in words by RameshNirmal).

Phalit jyotish aur vidnyan (in Hindi) [Astrology andscience], Tarksheel, 23.

Eka mahanagaracha mrutyu (in Marathi) [The death ofa megapolis], Loksatta, August 7.

Mahavidyalayanmadhyehi sanshodhan karya (inMarathi) [When exciting science is done in colleges, notin labs], (Translation of article appeared in Indian Expressdated October 22 under the “India empowered to meis” series), Loksatta, October 24.

Prithvibaheril jeevshristi (in Marathi) [Extraterrestriallife], Navakal, October 16, 20, 21 and 22.

Jagtikikaran : Kahi vichar (in Marathi) [Globalization:Some thoughts], Aashay, 43.

Ek upekshit shastradnya Alfred Wegener (in Marathi)[Alfred Wegener: A neglected scientist], Tonic, 18.

Project solspace (in Marathi) [Project solspace], ChhatraPrabodhan, Diwali Issue, 114.

Lambi, kshetraphal ani ghanaphal (in Marathi) [Length,area and volume], Shaikshanik Samachar Patrika, 9.

(c) Radio / TV Programmes

Ranjan Gupta

An interactive question/answer programme onAstronomy and Astrophysics, Doodarshan Silchar,Assam broadcast, February 28.

Ajit Kembhavi

Vigyan Chetna - Research in Astronomy, DoordarshanSilchar (National DD Panelists : Ajit Kembhavi, RanjanGupta and Asoke Sen; Anchor : Pavan Chakraborty;Participants : Six Students from M.Sc.and Ph.D.programme, February 20. Telecast on February 28 at 1800hrs.

J. V. Narlikar

Vidnyan Parichay (Akashwani, Pune, June 12, June 19,and June 26). Manacha Mujra, ETV (Marathi) ,October.

Participation in question-answer programmes on keychannels on television.

Occassional talks and interviews on All India Radio andon ETV (Marathi).

FACILITIES

(I) Computer Centre

The IUCAA Computer Centre continues to offerstate of the art computing facility to users fromIUCAA as well as IUCAA associates and visitorsfrom the universities and institutions in India andabroad Today everyone relies on wide-area net-works to connect employees, customers, partnersand vendors. As increasing amounts of email, peer-to-peer traffic and web browsing consume WANbandwidth, IT managers struggle to keep criticalapplications running at an acceptable levels of per-formance. Adding bandwidth a short-term solu-tion since traffic inevitably grows until performanceonce again becomes an issue. To over come thebandwidth issue, an appliance called Packeteer wasdeployed in June 2005. Packeteer gives IT man-agers a powerful tool that monitors, controls andaccelerates WAN traffic. It also ensures that theWAN delivers optimal performance and enhancesproductivity. IUCAA network has many MicrosoftWindows based clients, which are prone to vulner-abilities. In the past, the network was subjectedto virus attack that would deteriorate the overallperformances of the local network. TrendMicro Of-fice Scan suite 7.0 is a centrally managed antivirusserver, and was setup last year to tackle this is-sue. The automatic updates are done everyday onall clients. This has made the network practicallyvirus free. Astronomy is in the midst of a silentrevolution. Driven by the continued advancementof computing power, storage and detector technol-ogy, the size of observational data-sets is growingexponentially. Hence, high performance computinghas become an indispensable and enabling technol-ogy for modern astronomy and astrophysics. InJuly 2005, the high performance computing facility”Hercules” was upgraded to 8 nodes. It comprisesof 32 alpha processors , 76 GB RAM and 2 TBstorage to meet the demand of the HPC users.

(II) Library and Publications

During the period under review, the IUCAA libraryadded 252 books and 400 bound volumes to its ex-isting collection, thereby taking the total collectionto 20,690. The number of journals subscribed was130. Approximately 300 books were added to thecollection of the Muktangan Science ExploratoryLibrary.

The library has successfully installed the cdmirroring server and is currently in the process ofuploading the cdrom collection onto the server.

Access to additional e-journals published bythe American Institute of Physics and Springercontinues to benefit users, provided by the UGC

Infonet Consortia programme for e-subscriptions,initiated by INFLIBNET, Ahmedabad.

Following the meeting of the members ofthe Forum for Resource Sharing in Astronomy(FORSA), which was organized at the NationalCentre for Radio Astrophysics (NCRA), Pune,during July 26-27, 2004, consortia subscriptionswere initiated for Nature and Scientific Americanarchives.

IUCAA has full-fledged publications depart-ment that uses the latest technology and DTP soft-ware for preparing the artwork and layout of itspublications like the Annual Report, Quarterly bul-letin “Khagol”, Posters, Academic Calendar, Con-ference Proceedings, etc.

(III) Instrumentation Laboratory

The staff of the instrumentation laboratory havebeen involved primarily in four major projects inthe recent years - Focal Plane Array data acquisi-tion system, Near-infrared PICNIC Imager, Ultra-violet Imaging Telescope (UVIT) on ASTROSAT,and the IUCAA Girawali Observatory. The secondone among the above has been discussed elsewherein this report.

IUCAA Faint Object Spectrograph Camera(IFOSC) is the primary instrument on the directCassegrain port of the telescope. As part of thegeneral redundancy development programme forthe observatory hardware to minimize down time,work was initiated to develop and test a completestandby replacement for the EEV data acquisitionsystem, which is currently being used on IFOSC.All the individual electronic cards have now beenpopulated and the final testing of the individualcards are underway. In addition to the above, athinned back-illuminated 2K x 2K CCD was pur-chased from E2V and a new controller for this chipis being designed and fabricated.

At the time of last year’s report, a USB-baseddata acquisition system was under developmentand a Windows platform version of it was closeto completion. This version was eventually usedfor testing the Star250 CMOS detector, which is tobe used in photon counting mode on board UVIT.The tests were carried out to identify space quali-fied pieces from a large number of CMOS detectors.Single card controllers for STAR250 detectors andthe USB2.0 based data acquisition system devel-oped in the laboratory were used in two setups - onewith high speed (10 MHz) clocks running infinitelyfor Dynamic Burn In Tests and another with pre-configurable speeds, exposures and frame numbersfor Pre and Post Burn Tests (Image acquisition).The setups were installed at TIFR, Mumbai labora-tory, where actual Dynamic Burn In tests of thirtydetectors were carried out.

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A linux-platform based USB data acquisitionsystem is currently undergoing development andtesting in the laboratory. This is eventually ex-pected to replace the frame-grabber card based sys-tem, which currently being used on IFOSC andNIPI.

Another UVIT-related work, which is inprogress in IUCAA laboratory is the test setup forscattered light attenuation modelling of the UVITbaffle. Tests were carried out on a factor-of-twodownsized model baffle, by illuminating with laserbeams at different locations and incident angles andchecking the resultant scattered background at theimage plane. Scattering properties of a number ofsurface coating materials are also being explored.

(IV) IUCAA Girawali Observatory

The observatory project successfully has completedthree major milestones during the past one year:(i) completion of installation and system integra-tion, (ii) commissioning and hand over, and (iii)commencement of science operations. After thequick achievement of engineering first light in late2004 and the subsequent failure of the Cassegraindrive motors, the telescope system integration workcould restart in earnest only in October 2005, af-ter the monsoon season. Rapid progress was thenachieved with integration, testing and performancefine tuning. This phase culminated with the finalon-site acceptance tests being carried out in earlyFebruary 2006 and the handing over of the tele-scope to IUCAA on February 14, 2006.

In October 2005, a test set up was made atthe observatory off-telescope, for observers to startusing the IUCAA Faint Object Spectrograph andCamera (IFOSC), the primary back end instru-ment. In addition to giving the observers a chanceto familiarize with the instruments capabilities andlimitations, this provided a lot of vital feedback pri-marily for the instrument control software system.Most of these bug-fixes and functionality enhance-ments were then incorporated to enhance the sta-bility and usability of the software. A remarkableachievement of this was that due to the excellentstate of preparedness at IUCAA, scientific obser-vations could start at the observatory in January2006 itself. This provided an oppurtunity to actu-ally test the on-sky telescope performance param-eters like image quality, autoguiding accuracy, sen-sitivity, etc. at their limits before the telescope wasformally handed over to IUCAA. Figure shows thefirst deep sky (z = 3.9) object spectrum taken withIFOSC on January 19, 2006. The 3.5A resolution,30 min integration IFOSC spectrum is comparedwith 6A resolution, 1 hour integration INT spec-trum of the same source.

A second instrument for the telescope - a di-

rect imaging LN2 cooled CCD camera with 1340 x1300, 20 micron pixels was procured from Prince-ton Instruments, USA. This will be used in one ofthe Cassegrain side ports of the telescope and pro-vides high spatial sampling imaging capability. AUBVRI standard filter set also has been procured,which can be used both with the PI CCD cameraas well as IFOSC. The filter wheel and mountingarrangements for the camera were designed in thelaboratory and is being currently tested on the tele-scope. The development of a third instrument forthe telescope, the near-IR PICNIC Imager (NIPI)is discussed in another section of this report.

During the installation of the telescope, it wasrecognised that there was a problem with dust set-tling on the primary mirror and other optical sur-faces. Efforts to identify a technique for periodiccleaning of the mirror led to the development ofa CO2 snow-cleaning setup for the observatory,which has been effectively employed to keep theeffect of dust minimum. In order to meet the needfor re-aluminizing the optics, a coating plant isplanned to be set up at the observatory. An orderhas been placed with M/s. Hindhivac Ltd., Ban-galore, for providing a magentron sputtering basedmirror coating plant.

Since the hand over of the telescope, a group ofIUCAA astronomers have been carrying out scienceverification programmes at the observatory in orderto (i) familiarize with the system, (ii) develop effi-cient observing techniques, and (iii) to characterizethe performance and determine the limits that canbe achieved with photometry, spectroscopy and po-larimetry. These observations were carried out inservice mode with some participation from a fewinterest groups outside IUCAA too. Some of the re-sults from these observations are presented in Fig-ures and . In summary, the science verificationobservations indicate that the telescope, observa-tory and site are performing close to the expectedspecifications and in certain instances better. Thescience verification phase is coming to a conclusionnow, and the plan is to make the observatory avail-able for the astronomy community through timeallocation during the winter of 2006-’07.

In addition to the IUCAA laboratory staff (M.P. Burse, K. Chillal, P. Chordia, H. K. Das, S. Engi-neer, A. Kohok, V. B. Mestry, A. N. Ramaprakash,and S. N. Tandon) who were largely involved withthe technical set up of the observatory, a groupof astronomers (R. Gupta, Vijay Mohan, S. Ravin-dranath, and R. Srianand) have put in considerableefforts to carry out the science verification projects.

(V) Virtual Observatory- India

A Virtual Observatory (VO) makes possible thestorage of vast quantities of astronomical data,

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Figure 15: Quasar specturm at redshift 3.9

Figure 16: Open cluster King 17 V Band 10 arcmin across

Figure 17: Gravitational lens R Band, 1 arcmin across

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which can be retrieved over the internet and usedby astronomers, wherever they may be located inthe world. Virtual observatories have become indis-pensable tools in a situation, where vast quantitiesof data at different wavelengths are produced everynight by major observatories on the Earth and inspace. Data obtained at different wavelengths re-quires quite different techniques or analysis and ex-pertise, which takes a long while to develop. How-ever, the modern astronomer needs to take a multiwavelength approach to the study of astronomicalobjects, and it is necessary to have computationaltools and resources for meeting this requirement.

A network of virtual observatories, each withlarge data mirrors in one domain on the other, andtransparent and easy to use tools or analysis, will,therefore, prove to be a great boon to astronomers.With this in mind, virtual observatories have beenset up in several countries over the last few years,and significant progress has been made in develop-ing standards, data formats, query languages andsoftware for analysis, visualization and mining.

The Virtual Observatory-India (VOI) projectis a collaboration between IUCAA and PersistentSystems Pvt. Ltd. (PSPL), which is a major soft-ware development company in Pune, which exper-tise in data mining and related areas. The projectis funded by the Ministry of Communication andInformation Technology (MCIT) and PSPL. Thehardware platform for the project is located atIUCAA, while the software development is under-taken in close collaboration at PSPL and IUCAA.VO-I has developed several tools, which have foundwide acceptance in the international virtual obser-vatory community, and have been used in mak-ing new and exiting scientific discoveries, includingblack holes in galaxies and rare kinds of stars.

During the period of the report, the originalVO-I project came to an end, and a next genera-tion VO-I project has been started, again as a col-laboration between IUCAA and PSPL, and fundedby MICT and PSPL.

The projects undertaken by VO-I during theperiod of the report are as follows:

1) VOPlot: VOPlot is a 2D/3D plotting andvisualization package, designed for the VOTabledata format, which is a XML based standard forrepresenting astronomical catalogues. VOPlot sup-ports position plots, histograms, statistics, overlayplots, creating new columns from existing ones anda host of other functions. The most striking fea-ture of VOPlot is its ability to interact with otherexisting astronomical softwares e.g. Aladin (Sky-Atlas). It has been integrated in many Astronom-ical Data Archives such as VizieR, Hubble SpaceTelescope Archive, OpenSkyQuery Portal. VOPlotlets astronomers do complex plotting, visualisationand statistics completely online, without having to

download the data, and without having to issue anycommands as VOPlot is completely event-driven.It is developed using Java Technologies. A numberof important enhancements have been made to VO-Plot during the period of the report, which includethe use of multiple resources and multiple windows.

2) VOMegaplot: This is a tool used to providemuch of the functionality of VOPlot, when the datasets being studied involve millions of points. UsingVOPLot for such large data sets would mean pro-hibitive memory requirements, and to avoid whicha wholly new package has been developed. The toolpreprocesses the data base to be used, and createsa number of auxiliary files, which allow the plottingof millions of points in just seconds, on machineswith normal specifications. The preprocessing hasto be done just once for each catalogue, and fea-tures such as zooming, skyplots, etc are available.

3) VOStat: This was first developed as a VOcompatible tool for statistical analysis of large datasets, as a collaboration between groups in Caltechand Penn Sate University. In collaboration withthese two groups, VO-I is developing the next gen-eration VOStat, with many statistical tests and anew interface. VOStat is being integarted with VO-Plot, to provide to the community a very powerfultool.

(VI)IUCAA Radio-Physics Trainingand Educational Facility

IUCAA is setting up a novel Radio-Physics Train-ing and Educational Facility in collaboration withneighbouring National Centre for Radio Astro-physics (NCRA). During 2005-06, work continuedby J. Bagchi and NCRA collaborators towards setup of the 5 m radio telescope and the laboratory fa-cility for experiments and calibration instruments.These will form the back-bone of this radio astron-omy based educational and training laboratory. Aproposal has been submitted to NCRA towards aformal collaborative venture and negotiations areon to chalk out an efficient work plan agreeable toboth institutes for speedy completion of the projectin near future.

The main observational facility will be a 5-metreRadio Telescope meant for solar (radio-continuum)and galactic (21cm hydrogen line) observations,which will also be used for radio astronomy train-ing work for the benefit of university students andteachers. All major design parameters were fi-nalised for beginnning the construction of the radiodish antenna. During phase-I, only one radio dishantenna is to be set-up and its performance wouldbe carefully evaluated. Subsequently, in phase-II,a second similar (or better) radio telescope wouldbe constructed for interferometric work. This radio

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Figure 18: Top Panel: Two high efficiency feed systems fabricated by engineering students for 21cm (1420 MHz) radioastronomy observations. Left: A ‘Chaparral’ type feed horn containing multiple choke-rings or low-Q traps for higher gainand bandwidth. Right: A cavity backed dipole feed showing wide usable bandwidth range of 1.3 GHz. Lower Left Panel:The 21cm feed-horn is shown mounted at the focus of 4-m diameter radio antenna located at the GMRT observatory. LowerRight Panel: Raw data received with the 4-m radio dish antenna. It shows a complex 21cm hydrogen line spectrum fromthe direction of galactic Perseus and local arms. The x-axis shows Doppler shifted frequency in KHz, with red section denotingred-shift (+ve velocity) and the blue section denoting the blue-shift (-ve velocity). The y-axis is proportional to radio power orantenna temperature

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antenna will be used for Solar radio astronomy, 21-cm hydrogen line observations, 6.6 GHz Methanolmasers, and detection of strong extragalactic radiosources. In addition, it will serve as a vehicle forhands-on training in radio astronomy instrumen-tation and observational disciplines. Furthermore,this radio telescope and receiver system can also beused for SETI experiments (i.e., search for extrater-restrial intelligence) when operated at the 1420.4MHz spin-flip transition frequency of neutral hy-drogen.Significant efforts were made by J. Bagchi andNCRA collaborators to promote Radio Astron-omy in schools and colleges by way of lecturesand many interesting hands-on type observationaland instrumentational projects. As an example,A group of B.Tech. students from Pune’s WadiaInstitute of Technology (electronics and commu-nication engineering), under the guidance of Ra-jaram Nityananda (NCRA), M.R. Sankararaman(NCRA), and J. Bagchi (IUCAA) used the proto-type 4-metre diameter radio dish antenna locatedat the GMRT observatory for their project. Formaking radio observations with this small dish an-tenna, they also designed, fabricated and lab-testeda couple of innovative feed-horns operating at the21-cm wavelength hydrogen band, as part of theirproject work [Figure 18] The electromagnetic per-formances of these students assembled feeds werefound to be very good. High gain, low loss, andand a broad usable frequency range was achieved.These improved feed systems will be eventuallyused with the proposed IUCAA 5 m radio tele-scope, along with the front-end amplifiers and re-ceivers for sky observations and radio astronomytraining work.

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IUCAA REFERENCE CENTRES (IRCs)

[1] Delhi University(Coordinator: T. R. Seshadri)

During the period, 2005-2006, renovation of the IRCpremises was completed, these were reoccupied by theIRC, and regular work was started afresh. There wereseveral visitors and talks. There was an essay competitionheld for school students, in collaboration with Centrefor Science Education, University of Delhi. V. S. Varmadonated several books to the IRC library. Already, thereare books lent on long term loan by IUCAA and booksdonated by V. B. Bhatia. The students are developing asoftware for keeping track of these books in the IRC.

Talks

B. Biswal: Chaos control in epilepsy, November 24.A. Pradhan: Kaluza-Klein type RW cosmological modelwith dynamical cosmological term Ë, December 30.N. Okada: Low scale minimal SUGRA model andcollider phenomenology on hidden sector fields, January17.K. K. Dutta: On the physics ideas behind the Nobel Prizefor 2005, January 31 and February 3.

Visitors

Ranjan Gupta (IUCAA, Pune), Arvind Paranjpye (IUCAAPune), M. Varadharajan (RRI, Bangalore) and A. Pradhan(Ghazipur)

Other ActivitiesEssay Competition for School Students

Title: The most significant physics discovery since 1950.43 entries were received from different schools.

[2] Pt. Ravishankar Shukla University, Raipur(Coordinator: S. K. Pandey)

Faculty members, research scholars and students in thedepartment as well as visitors have made use of thefacilities available at the centre in strengthening theirteaching/research activities in the field of A & A.

(a) Teaching: M.Sc. students of the department madeuse of the INTERNET facility for browsing anddownloading articles useful for their studies. M.Sc. finalyear students, who had opted for A & A as specializationfor their M.Sc. course used IRC facilities (INTERNETand library) in carrying out their project work. New state-of-the-art telescopes (CGE800 and CGE1400) anddetectors (photometer and CCD spectrograph, etc.)procured under DST-FIST have helped the departmentin resuming observational exercises/projects inastronomy for the M.Sc. students.

(b) Research: the research activity of the faculty membersand the research students is mainly focused in followingareas:

(i) Dynamical modeling of elliptical galaxies carried outby D. K. Chakraborty and his research students.

Dr. Chakraborty is currently engaged in the study ofintrinsic shapes of elliptical galaxies using photometricdata. Research students working with him include ArunKumar Singh, Firdaus and Arun Diwakar. Singh andFirdaus attended the YAM-2005 held at IUCAA andpresented poster papers. A paper entitled “Variation ofintrinsic shapes using photometry” has been submittedfor publication and is currently under revision.

(ii) Research on Multi-wavelength surface photometryof early-type galaxies Has been carried out by S.K.Pandey and his research students, as a part ofcollaboration with A.K. Kembhavi and people from otherinstitutes/observatories. The main objective of theresearch programme is to study properties of dust inextragalactic environment, and also to examinerelationship of dust with other forms of ISM in thesegalaxies. A subsample of 10 nearby dusty ellipticalgalaxies were imaged in BVRI and H-alpha during 2005-2006 using the 2 m HCT of IIA. Preliminary data reductionis complete and detailed analysis of the dust is inprogress. Laxmikant Chaware and S. Kulkarni areinvolved in this project.

(iii) Study of chromospherically active stars: SudhanshuBarway has completed his thesis work in this area; heworked as SRF in a CSIR sponsored project andsubmitted his Ph.D thesis to the University duringDecember 2005.

Other important activity of the centre has been toencourage M.Sc. students of the department to applyfor summer schools/programmes, etc. of various institutesin the country. Applications of ten students from M.Sc.were forwarded by the IRC co-ordinators for the summerschools/summer projects to the institutes like IUCAA,NCRA, IIA, ARIES, and PRL. Four students of M.Sc.students got selected for summer school and VSP ofIUCAA.

Talks

A. R. Rao: Probing black holes using X-rays, July 30.P Sreekumar: Chandrayaan-1: India’s first mission tothe Moon, July 30Ashish Mahabal: Research avenues in A & A, December24

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Lectures/ Radio talks delivered by S.K. Pandey

S. K. Pandey : Bhartiya Antix Karyakrama Ke VividhAayam (Hindi Roopak), February 19 (Radio talk/interview).S. K. Pandey: A physicist view of the universe, SriShankarcharya College of Engg. & Tech., Bhilai, April19.S. K. Pandey: Our universe, CMD P.G. College, Bilaspur,September 6.S. K. Pandey: How well do we know our Universe, BSPSr. Sec. School, September 23.S. K. Pandey: Discovering the cosmos, Disha College,October 1.S. K. Pandey: Inaugural lecture on lfe-cycle of stars,Physics Society at Kalyan Mahavidyalaya, Bhilai Nagar,November 12.S. K. Pandey: A glimpse of the universe (in Hindi),National Science Festival for School students, SCERT,Chattisgarh Govt., November 15.S. K. Pandey: Discovering the universe, Bhilai NairSamajam College, Bhilai, November 19.

Visitors

Vivek Agrawal (ISRO, Bangalore), A.R. Rao (TIFR,Mumbai), P. Sreekumar (ISRO, Banglore), SubhashKaushik (Govt. College, Datia (M P)), M.K. Patil (SRTMUniv., Nanded), Ashish Mahabal (Caltech, USA), LaisramDharendra (Manipur University).

Other ActivitiesSky gazing programme

On March 29, 2006 a public show of partial solar eclipsewas organized using the 8-inch telescope fitted with solarfilter, and this attracted attention of media/localnewspaper.

[3] North Bengal University, Siliguri(Coordinator: S. Mukherjee)

In addition to the usual visitors and lecture activities, anIntroductory Workshop on Astronomy and Astrophysicswas organized at J. K. College, Purulia, West Bengalduring February 23-25, 2006. The programmes includedlectures by Professors A. K. Kembhavi, R. Gupta (bothfrom IUCAA), S. Kar (IIT, Kharagpur), S. Raha (BoseInstitute, Kolkata) and S. Mukherjee (North BengalUniversity), discussion sessions, and night skyobservations, which was conducted by scientists ofPositional Astronomy Centre, Kolkata. About 80 studentsand 20 college teachers participated in this workshop. S.Mukherjee and A. Kembhavi were the academic Directorsof the workshop.

Talks

G. Singh: Liquid-gas phase transition through projectilefragmentation at relativistic energy, April 19.R. Tikekar: On relativity and cosmology, April 26.A. Bhattacharyya: Mixed surfactant poly-electrolytesystems: Surface rheology and other properties, May17Amit Chakraborty: Carbon Nano-tubes and itsapplication to nano-technology, April 29Prabasaj Paul: Visualizing Relativity, November 28T. R. Govindarajan: Einstein’s legacy and quantumgeometry, December 9S. Mondal: Bringing physics to Life,Biswajit Paul: Sky watching in X-rays and the IndianExperiments,M. Narlikar: Fun with mathematics, March 23.J. V. Narlikar: Gravitational collapse with negativeenergy fields, March 24.

Visitors

B. Bhattacharjee, J. V. Narlikar (IUCAA, Pune), M. Narlikar(Pune), P. Chattaopadhyay, P. Thakur.

Other ActivitiesEssay Competition for School Students

52 essays (32 Bengali and the rest in English) weresubmitted. There were entries from North Bengal, NorthEastern States and Sikkim. The results of the competitionhave recently been announced. The first three entrieswill receive cash prizes. The authors of the next ten bestentries will receive certificates of merit.

[4] Cochin University of Science and Technology, Kochi(Coordinator: V. C. Kuriakose)

The facilities available at IRC has been regularly usedby both M.Sc. students for their project work andPh.D. students and the faculty members. Talks, Seminarsand colloquia were held under the joint auspices of IRCand the department. The colloquia gave a chance toIUCAA Associates of this region to present their andtheir students’ works and helped them to interact withothers. The colloquia were attended by students andFaculty members who are not IUCAA Associates. TheIRC Library contains 47 books and 4 computers and aprinter. Internet connectivity is also provided in the IRCroom. February 28th was celebrated as National ScienceDay and the film on Professors A.K. Raychaudhuri andP.C. Vidya was screened on the occasion. Students fromneighbouring institutions also come for using the libraryfacilities. IRC also conducted an essay competition forthe students of Higher Secondary School as part ofthe celebration of WYP 2005.

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Talks

K. Babu Joseph: Quantum coherence.R. Vijaya: LasersA. Kembhavi: Gravity and Light: Journey from lightbending to cosmic lenses.C. D. Ravikumar: The Cosmic dance: Galaxyinteractions.Bala R. Iyer: Gravitational waves.M. Sabir: Quantum computing.K. P. Vijayakumar: Effect of doping on the properties ofZnO thin films.Ramesh Babu T: Quantum coherence.K. J. Saji: Plasma diagnosis: Controlling growth of thinfilms.P. I. Kuriakose: No-hair theorem, October 25.Moncy V. John: Was there a decelerating past for theuniverse?, October 25.K. S. Sumesh: Irregular pulsation in the mira vaiableRhydrae, October 25.K. Ambika: Patterns and their dynamics in Gumoski Miramap, October 25.Jisha C. P.: Spatial solitons, October 25.K. P. Harikrishnan: Stochastic Resonance withmultisignal inputs, November 19.V. C. Kuriakose: Quantum computing using Josephsonjunctions, November 19.R. Radhakrishnan: Higher order stark correction inatomic hydrogen, November 19.R. Sini: Black hole scattering, November 19P. B. Vinodkumar: Different notions of chaos, November19.

Visitors

Ninan Sajeeth Philip (St. Thomas College, Kozenchery),T. Padmanabhan (IUCAA, Pune), A. Kembhavi (IUCAA,Pune), Bala R. Iyer (RRI, Bangalore), C.D. Ravikumar(GEPI, The Paris Observatory, Meudon), R.Vijaya (IITBombay), P.P. Divakaran (IMSc., Chennai), K. Porsezian(Pondicherry University).

Other ActivitiesEssay Competition for School Students

IRC has organized an essay competition for students ofHigher Secondary Classes in Kerala. 75 studentsappeared for the competition. First prize was notawarded as advised by the judges. Second and third prizesand certificates of merit for the next 10 students weregiven.

Lecture series : Professor T. Padmanabhan gave a seriesof lectures on “Aspects of Gravitation” during August10-14, 2005. This was attended by the M.Sc. students,and research scholars and faculty members of thedepartment. He also led an interactive session with HigherSecondary School students from neighbouring schools.

[5] Jadavpur University, Kolkata(Joint Coordinators: Narayan Banerjee and Asit Banerjee)

The Centre organized a few public lectures and someseries of lectures and workshops in addition to the regularseminars. Some of the members participated in variousactivities like taking part in conferences, workshops andalso giving popular lectures. An essay competition wasorganized for High School students. In the lovingmemory of Professor A. K. Raychaudhuri, a two dayseminar was organized, spread over two successiveTuesdays. Five of his Ph.D. students talked about theirwork that they did under his supervision.

In addition to the regular Tuesday seminars at the Centre,public lectures were organized to celebrate the Year ofPhysics.N.Panchapakesan and C.V.Vishveshwaradelivered two lectures, which were aimed at a wideraudience. These lectures were well attended. They alsogave a series of technical lectures, Panchapakesan oncosmology and Vishveshwara on black holes. Visitorslike Naresh Dadhich, S. Mishra and T. K. Das gaveseminars which were attended by senior students alongwith the regular members of the Centre. G.M.Hossainconducted five lecture workshop on Loop QuantumCosmology. This workshop was also attended by researchstudents from other institutes.

Members of the Centre, Asit Banerjee and NarayanBanerjee went to different colleges and gave talks forundergraduate students as a part of celebration of theInternational Year of Physics.

Narayan Banerjee gave a lecture at the IUCAA workshopat St. Xaviers College, Kokata He also gave a course onCosmology at the AKR Gravity School organized at SahaInstitute of Nuclear Physics.

Visitors

N. Panchapakesan (University of Delhi), Ranjeev Mishra(IUCAA, Pune), Naresh Dadhich (IUCAA, Pune), GolamMortuza Hossain (IMSc, Chennai), Tapas Das (HRI,Allahabad), C. V. Vishveshwara (Bangalore).

Other ActivitiesEssay Competition for School Students

IRC organized an essay competition for High Schoolstudents on ‘The most important milestone in twentiethcentury physics’ as a part of celebration of theInternational Year of Physics. There was a very goodresponse as around 100 essays were enrolled for thecompetition. The results were declared in December 2005.

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[6] D.D.U. Gorakhpur University(Coordinator: D. C. Srivastava)

At the centre, visitor scientists use the library and theinternet facility. Their seminar/ lectures are also organized.Weekly seminars by the faculty members and researchscholars are held in the department. These provide anopportunity for interaction and exchange of ideas. Thelibrary contains the books loaned by IUCAA. At presenta dial up internet facility is available. IRAF: an imageanalysis software is being used at centre. AIPS is alsobeing installed for analysis of radio data. These and otheractivities detailed below are growing at normal pace.

Talks

D. K. Tripathi: Studies of solar coronal mass ejection,April 02.Ram Sagar: Recent devlopments in observationalastrophysics, October 06.Ram Sagar: Relevance of astrophysics in modernscience, October 07.

Visitors

Durgesh Kumar Tripathi (Max-Planck Institute forAeronomy, Lindau, Germany), S. S. Prasad (U.N. P.G.College, Padrauna), B. K. Sinha (Institute of Pharmacy,V.B.S. Purvanchal University, Jaunpur), Ram Sagar(ARIES, Nainital).

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