RUDRANI KAR CHOWDHURY

PRESIDENCY UNIVERSITY M.Sc thesis advisor

Suchetana Chatterjee

X-ray Surface Brightness Profiles of Galaxy Groups from Cosmological

Simulations

Analytic models and numerical simulations of cluster formation predict that temperature and X-

ray luminosity are related as

but observation shows that

2TLX

3TLX

Lx – T Relation in Galaxy Groups/Clusters

Andersson et. al 2009

2.98 0.19 for 0.069<Z<0.2 (red circles) 2.62 0.21 for Z>0.2 (green triangles) 2.69 0.18 for cooling clusters (blue squares)

Some other effect seems to be responsible for changing the LX-T slope. One possibility is AGN Feedback

CENTRAL SUPERMASSIVE BLACK HOLE IN A GALAXY ACCRETING MASS FROM

THE SURROUNDINGS

ACTIVE GALACTIC NUCLEI (AGN)

AGN FEEDBACK IN GALAXY CLUSTERS

HST image of MS0735.6 + 7421 cluster

Chandra X-ray image in blue

VLA radio image in red

McNamara & Nulsen 2007

OTHER OBSERVATIONAL PROOF OF AGN ACTIVITY

Cooling flow problem in galaxy clusters Cosmic downsizing

Using two cosmological hydrodynamic simulation we now want to study the effect of feedback on the X-ray surface brightness profile of galaxy groups. Both simulation starts from the same initial conditions. One set includes a model of AGN feedbackOne set does not include AGN feedback.

Aim of this Work

COSMOLOGICAL SIMULATION

The simulation used in this purpose has the following properties….

Box size Total no. of particles in the box Total no. of particles is the sum of cold dark matter

particles gas particles, star particles and black hole particles.

Mass of dark matter is Mass of gas particles is

32162

Mh 181075.2

Mh 171024.4

Mpc34

Simulation Snapshot

Density of gas color coded by temperature. Yellow circles represent black holes. Dark matter and stars are not shown in this plot.

DiMatteo et al. 2008

BLACK HOLE FEEDBACK Seed black hole grow in size by accreting mass from the surrounding Accretion rate is given by

Luminosity of the black hole is

Feedback energy is

2/32222 )/()(4 vcMGM

2CMLr

rf LE

METHODOLOGY Spherical region of radius 100 kpc is considered around the black hole X-ray map is constructed by allocating spatial grids to the region of space and computing smoothed x-ray flux at a given grid point To construct the x-ray surface brightness profile , map is divided into a no. of annular regions and x-ray flux of each region is calculated and a differential profile of flux is made as a function of distance

Mass of 2nd most massive BH at Z=3 is Accretion rate is Mass of the host halo of this black hole

Mh 181015.7

yearM /240.0

M131071.4

RESULT

The left panel shows the X-ray map with feedback for 2nd most massive black hole at Z=3. The right panel shows the x-ray map without feedback for the same black hole

This is the differential profile of x-ray flux for with (dotted line) feedback and without feedback (solid line) cases

Conclusion and Future Work Without AGN feedback the x-ray flux is high at the centre X-ray flux is low at the centre & high outside when AGN activity is considered Our result is in accordance with the observation by McNamara & Nulsen We have studied this AGN activity for one red shift & one black hole In future our plan is to study this effect for more than one red shift & black hole

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