Search for Gravitational Wave Transients - Rencontres de Moriond
Quasi-normal mode oscillations. GW. Both Hanford detectors were up at that time. Ringdown signal is searched â No detection. Upper limits on GW energy ...
Specific vetoes based on auxiliary channels have been produced to remove specific glitch families Veto safety have been carefully checked (we don't want to flag real signals!)
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Rencontres de Moriond - March 2011
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SNR
100
Florent Robinet
CBC Searches
BNS BBH BHNS
S5/VSR1 data have been analyzed and results are published "Realistic" observable BNS coalescence rate ~ 0.02 per year (large uncertainty)
Rencontres de Moriond - March 2011
S6/VSR2-3 analyses are in progress Preliminary results are released See T. Dent's talk 22
Florent Robinet
CBC: Low Mass Search Description of the search:
No Detection
Non-spinning templates ● Post-Newtonian up to the innermost stable orbit ● Mass region 2 < M < 35 Msun total ●
Phys. Rev. D 82(2010) 102001
BNS/BBH Upper limits
Rencontres de Moriond - March 2011
NS/BH Upper limits
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Florent Robinet
CBC: High Mass Searches High-Mass ● Effective One Body (EOB) waveforms ● Inspiral-Merger-Ringdown is covered ● No spin ● Mass region 25 < M < 100 Msun total ● Uncertainty on the waveforms ● LIGO only search (Virgo is not sensitive enough for High mass systems)
arXiv:1102.3781 Rencontres de Moriond - March 2011
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Ringdown search ● In progress for S5 ● LIGO only search ● Mass region 75 < MBH < 750 Msun ● Spin is included ● The ringdown contains most of the GW energy ● More reliable waveforms Florent Robinet
CBC & Burst Signals: GRB Triggered Searches Powerful bursts of highly energetic gamma rays Two populations: short and long duration Short: possibly produced by the merging of binary objects → CBC colored search Long: possibly produced by violent stellar collapse (hypernovae)
Number of Bursts
Long-duration Short-duration GRBs GRBs 60
Use mainly Swift and Fermi triggers to get a source location a timing and sometimes a distance Background reduction Better sensitivity
40
During S5/VSR1 137 GRBs were analyzed by the burst coherent pipeline (short and long). See M. Was's talk
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0.1
1 10 T90 (seconds)
Rencontres de Moriond - March 2011
22 GRBs were analyzed by a CBC pipeline. See N. Christensen's talk 25
Florent Robinet
CBC & Burst Signals: GRB Triggered Searches GRB 070201 Short and hard GRB detected by 4 satellites in Feb. 2007 in direction of the Andromeda galaxy
The binary merger scenario is excluded with a 99% confidence level! Astrophys. J. 681(2008) 1419 Inspiral Exclusion Zone 25% 50% 75% 90%
Description of the search ● Multiple Algorithms ● Broad-band frequency search ● Coincident and coherent searches ● Very large variety of waveforms ● Robustness
Rate (90% C.L.) vs. frequency (EGW = Msunc2)
No detection With a 90% confidence level, the rate of burst signals with 50 < f < 2048 Hz is lower than 2 events per year
1e-2 yr-1 Mpc-3
~8e-7 yr-1 Mpc-3
Phys. Rev. D 81(2010) 102001 Rencontres de Moriond - March 2011
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100
f(Hz)
1000
Florent Robinet
Burst Signals: Neutron Stars 2006/08/12: timing glitch observed in the radio emission of the Vela pulsar Quasi-normal mode oscillations
GW
Both Hanford detectors were up at that time Ringdown signal is searched → No detection Upper limits on GW energy released by monoharmonic modes Phys. Rev. D83(2011) 042001
Soft Gamma Repeaters (SGR) / Anomalous X-ray Pulsars (AXP) Neutron stars powered by extreme magnetic fields (magnetars) SGR 1900+14 SGR 0418+5729 SGR 1627-41 SGR 1806-20 SGR 0501+4516 AXP 1E 1547.0-4508
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6 magnetars have been analyzed by a dedicated pipeline (excess power)
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Rencontres de Moriond - March 2011
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arXiv:1011.4079 Florent Robinet
Burst Signals: Cosmic String Cusps When 2 cosmic string segments meet they can reconnect and produce loops. The main mechanism for the loop to loose its energy is to radiate gravitationally.
GW radiation is the most promising signature to detect cosmic strings. GW
Points of the string can acquire a large Lorentz boost and form a "cusp" → GW burst
GW Well-modeled signal Template burst search Dedicated pipeline Upper limits on the cosmic string parameter space:
S5 Projection
Gμ: String tension
S4
ε: loop size parameter p: reconnection probability Phys Rev D 80(2009) 062002 Rencontres de Moriond - March 2011
Gμ
30
10 –7
10 –6
Florent Robinet
Online Searches Hanford h(t)
Livingstone
Virgo
h(t)
Low latency searches took place during S6 / VSR2-3 for both CBC and burst searches
h(t)
Central Location h(t)
CBC pipeline MBTA event
h(t)
Burst pipeline Omega
h(t)
Burst pipeline Coherent Waveburst
event
event
Candidate Database
~ 30 min
Most significant events were sent to telescopes / satellites (14 events for S6/VSR2-3) Sky localization is performed with a resolution of ~tens of square degrees for events at threshold Image analysis is performed within the collaboration
Most significant Candidate selection
See M. Branchesi's talk
Swift
Zadko
ROTSE
Rencontres de Moriond - March 2011
Florent Robinet
S6/VSR2-3 Science Run
Improved sensitivity ~ 200 days of live-time with at least 2 detectors up Big challenge: run analyses online – 3 pipelines were running (2 bursts + 1 CBC) – The data quality was performed with low latency (< 1 min) – EM follow-up by partner telescopes Offline analyses are in progress (some results are released) Analyses pipelines and data quality tools have been improved for a better sensitivity Blind hardware injection challenge was successful (we detected it with great confidence). See T. Dent's talk
Rencontres de Moriond - March 2011
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Florent Robinet
Preparation for Advanced Detectors Era Sensitivity improvement by a factor 10 This translates into a detection rate up to 40 neutron star binary events per year Science should resume in 2015 Design sensitivity achieved by 2019
What are we going to do in the meantime ? Virgo might run this summer (VSR4) along with the GEO detector Similar sensitivity at high frequency This run could be of some interest for external triggered searches Then GEO will run alone in astrowatch mode during the construction of Adv. detectors (2012-2015) Some mock data runs are planned to test and improve our searches A lot of work is required to optimize the EM-followup procedures
Rencontres de Moriond - March 2011
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Florent Robinet
Summary - Conclusions A large variety of physical results have been produced from the LIGO-Virgo data There is no detection yet but upper limits can be used to constrain astrophysical models The first generation of detectors is close to the end. – Analysis pipeline have greatly improved over the last years to perform optimized and sensitive searches on GW data – Data quality is a great challenge. Multiple tools have been developed to reject noise events efficiently. – GW astronomy is on its way: online searches, Multi-messengers, EM followup Now, the big challenge is to be fully ready for the Advanced Detectors Era
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order to find the beginning of a valid plan that can lead to a reachable state, that will of- ... This lookahead strategy can be used in different search algorithms. ...... 7All domains and problems used in our experiments can be downloaded on the ..
