Upload
duongnga
View
221
Download
0
Embed Size (px)
Citation preview
24-June-05 Amaldi-6 - Barish 2
Towards Detection of Gravitational Waves
From LISA Concept Demonstrations Mission
From Bars Bars with Increased Bandwidth Spheres
From Interferometers Advanced Interferometers Next Generation (QND) Detectors
From 8 Mpc (NN inspiral) 200 Mpc and then beyond
From Upper Limits Searches Detections
From Generic Searches Searches with Specified Waveforms
From Single Detectors Global Networks
24-June-05 Amaldi-6 - Barish 3
Gravitational Waves in Space
LISA
Three spacecraft, each with a Y-shaped payload, form an equilateral triangle with sides 5 million km in length.
24-June-05 Amaldi-6 - Barish 7
Total number of detatched binaries 208736473
Total number of interacting binaries 34291253
Distribution of WD binaries (Nelemans et al)
WD-WD, WD-NS, NS-NS binaries with GW frequency within LISA band are observed.
These sources are GUARANTEED
Krolak
24-June-05 Amaldi-6 - Barish 8
Data Analysis Issues
Stochastic signal Isolated signals
Interacting signals
Long wavelength regime Short wavelength regime
TDI
LISA motion; long observation times; network of detectors
Krolak
24-June-05 Amaldi-6 - Barish 12
Sensitivity of DECIGO
Force noise= 1/100 of LISA’s
10–4 10–3 10–2 10–1 100 101 102 10310–25
10–24
10–23
10–22
10–21
10–20
10–19
10–18
Frequency [Hz]
Stra
in
[1/H
z1/2 ]
LCGT
LISA
DECIGO(LISA type, 5x104km)
DECIGO(FP type, 1000km)
Laser: 10W, 532nmMass: 100kgMirror: 1m dia.
24-June-05 Amaldi-6 - Barish 13
ExplorerSwitzerland
Allegro USA
SchenbergBrazil
MiniGrailThe Netherlands
NiobeAustralia
Nautilus, italy
Auriga, ItalyResonant Bar Detectors
24-June-05 Amaldi-6 - Barish 15
“spheres”• omnidirectionality: decode the excitation of the 5
quadrupolar modes to get uniform sky coverage & find direction of propagation
• cross section: larger as the volume fill-up factor inrespect to bars
MiniGRAIL (Leiden-Rome) just started operationTalks of Annette de Waard
and Luciano Gottardi
Schenberg (Brasil) coming to
sensitive in a few kHz-wide freq band !!!
GW signals addback action noises subtract
read-out with non-resonating transducers the differential deformations at frequencies between the lowest quadrupolar modes
DUAL: two nested resonant massesCerdonio et al PRL (2001), Bryant et al PRD (2003), Bonaldi et al PRD (2003)
talk by Michele Bignotto
24-June-05 Amaldi-6 - Barish 19
International Gravitational Event Collaboration (IGEC)
ALLEGRO,AURIGA,EXPLORER, NAUTILUS, and NIOBE 1997-2000.
The search for burst waves at resonant frequency ~ 900 Hz.
The detectors nearly parallel to maximize coincident sensitivity.
Candidate events at SNR > 3-5 (~ background events 100/day)
Data exchanged: peak amplitude, time of event and uncertainties.
Threshold equivalent to ~0.1 M converted into a gravitational wave millisecond burst at a distance of 10 kpc.
The accidental coincidence rate over 1 sec interval (e.g. bandwidth of 1 Hz) was ~ few/week two-fold and ~few/century three-fold.
Time resolution not sufficient to resolve incident wave direction, no directional search has been applied.
No evidence for grav wave bursts was found.
24-June-05 Amaldi-6 - Barish 20
rate[y –1]
search threshold h
1.E+00
1.E+01
1.E+02
1.E+03
1E-18 1E-17 1E-16
IGEC
h ~ 2 10-18 ΔE ~ 0.02 M converted @ 10 kpc
The Area above the blue curveis excluded with a coverage > 90%
Upper Limit on the Rate of gravitational waves bursts from the GALACTIC CENTER
random arrival times and amplitude ≥ search threshold h
[P. Astone, et al. Phys. Rev. D68 (2003) 022001]
IGEC coincidence search
Final results
24-June-05 Amaldi-6 - Barish 21
During 2001 EXPLORER and NAUTILUS were the only two operating resonant detectors, with the best ever reached sensitivity.An algorithm based on energy compatibility of the event was applied to reduce the “background”
EXPLORER-NAUTILUS 2001
Sidereal hours
Num
ber o
f eve
nts
ROG Coll.: CQG 19, 5449 (2002)L.S.Finn: CQG 20, L37 (2003)P.Astone, G.D’Agostini, S.D’Antonio: CQG Proc. Of GWDAW 2002, gr-qc/0304096E. Coccia ROG Coll.:CQG Proc. Of GWDAW 2002ROG Coll.: gr-qc/0304004
New data needed
Excess ???Direction of Galactic Disc
24-June-05 Amaldi-6 - Barish 22
ROG S 03ROG S 01 suggestion
- crewless operation- data validated by cosmic ray effect- new upper limit with bars, no significant coincidence excess nor sidereal effect.
EXPLORER NAUTILUS Science Run 03
24-June-05 Amaldi-6 - Barish 23
IGEC-2Expected Performance
Triple coincidences: 106 time shifts, no accidentals, 9.3 days false alarm rate < 10-4 / yr for H>1.4 10-21/Hz
Double coincidences:lower false alarm rates than for IGEC-1
rate[year –1]
search threshold
dashed region excluded with probability
> 90%
My best guess on the achievable upper limit improvement by IGEC-2
WARNING:incomplete data set !
1 month
1 year
IGEC-1 upper limit
24-June-05 Amaldi-6 - Barish 24
InterferometerDetectors
LIGO Louisiana 4000mTAMA Japan
300m
Virgo Italy 3000m
GEO Germany 600mAIGO Australia
future
LIGO Washington 2000m & 4000m
24-June-05 Amaldi-6 - Barish 29
Results for Neutron Star Binaries
Event Candidates» 142 event candidates found in
the data» Loudest candidates
eliminated in follow up investigation…
» Other candidates consistent with background of analysis pipeline
Upper limit set on the rate of BNS coalescences
R90 = 47 / year / MWEG
24-June-05 Amaldi-6 - Barish 30
Results for Primordial Black Hole Binaries
Same analysis pipelineEvent rate consistent with background of analysis pipelineUpper limit set on the rate of PBHB coalescences
R90 = 63 / year / MWEG
24-June-05 Amaldi-6 - Barish 31
-16 -14 -12 -10 -8 -6 -4 -2 0 2 4 6 8
-14
-12
-10
-8
-6
-4
-2
0
Log ( f [Hz])
Log(Ω
0h10
02)
f ~ H0 - one oscillation in thelifetime of the universe
f ~ 1/Plank scale – red shifted fromthe Plank era to the present time
-18 10
Laser InterferometerSpace Antenna - LISA
Inflation
Slow-roll
Cosmic strings
Pre-big bangmodel
EW or SUSY Phase transition
Cyclic model
CMB
Pulsar Nucleosynthesis
LIGO band
Stochastic BackgroundPredictions and Experimental Limits
LIGO S1, 2 wk dataΩ0h100
2 < 23 PRD 69(2004)122004
(H2-L1)
Advanced LIGO, 1 yr data Expected Ω0h100
2 < 7x10-10
(H1-L1)
LIGO S3, 2 month dataΩ0h100
2 < 4.4x10-4
(H1-L1) presented hereInitial LIGO, 1 yr data Expected Ω0h100
2 < 2x10-6
(H1-L1)
24-June-05 Amaldi-6 - Barish 32
ConclusionsSensitivity toward gravitational wave detection is improving on many fronts and this will continue well into the future
New upper limits are being set for the major sources --binary inspirals, periodic sources, burst sources and stochastic background.
Data exchange and joint data analysis between detector groups is improving our ability to make detections
Many exciting future projects and upgrades are planned or getting underway.
Hopefully, detections will be made soon !! Maybe by Amaldi-7??