A. M. Gretarsson

Publications (133)205.74 Total impact

• Article: Parameter estimation for compact binary coalescence signals with the first generation gravitational-wave detector network

  the LIGO Scientific Collaboration, the Virgo Collaboration, J. Aasi, J. Abadie, B. P. Abbott, R. Abbott, T. D. Abbott, M. Abernathy, T. Accadia, F. Acernese, [......], M. Yvert, A. Zadrożny, M. Zanolin, J. -P. Zendri, F. Zhang, L. Zhang, C. Zhao, N. Zotov, M. E. Zucker, J. Zweizig
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  ABSTRACT: Compact binary systems with neutron stars or black holes are one of the most promising sources for ground-based gravitational wave detectors. Gravitational radiation encodes rich information about source physics; thus parameter estimation and model selection are crucial analysis steps for any detection candidate events. Detailed models of the anticipated waveforms enable inference on several parameters, such as component masses, spins, sky location and distance that are essential for new astrophysical studies of these sources. However, accurate measurements of these parameters and discrimination of models describing the underlying physics are complicated by artifacts in the data, uncertainties in the waveform models and in the calibration of the detectors. Here we report such measurements on a selection of simulated signals added either in hardware or software to the data collected by the two LIGO instruments and the Virgo detector during their most recent joint science run, including a "blind injection" where the signal was not initially revealed to the collaboration. We exemplify the ability to extract information about the source physics on signals that cover the neutron star and black hole parameter space over the individual mass range 1 Msun - 25 Msun and the full range of spin parameters. The cases reported in this study provide a snap-shot of the status of parameter estimation in preparation for the operation of advanced detectors.
  04/2013;
• Source

  Available from: David Chin

  Dataset: First Cross-Correlation Analysis of Interferometric and Resonant-Bar Gravitational-Wave Data for Stochastic Backgrounds - Phys. Rev. D 76 (2007) 022001

  B. Abbott, R. Abbott, R. Adhikari, J. Agresti, P. Ajith, B. Allen, R. Amin, S.B. Anderson, W.G. Anderson, M. Arain, [......], N. Yunes, M. Zanolin, J. Zhang, L. Zhang, P. Zhang, C. Zhao, N. Zotov, M. Zucker, H. Zur Muhlen, J. Zweizig
• Source

  Available from: David Chin

  Dataset: Upper limit map of a background of gravitational waves - PHYSICAL REVIEW D 76, 082003 (2007)

  B. Abbott, R. Abbott, R. Adhikari, J. Agresti, P. Ajith, B. Allen, R. Amin, S.B. Anderson, W.G. Anderson, M. Arain, [......], S. Yoshida, N. Yunes, M. Zanolin, J. Zhang, L. Zhang, C. Zhao, N. Zotov, M. Zucker, H. Zur Muhlen, J. Zweizig
• Article: Search for Gravitational Waves from Binary Black Hole Inspiral, Merger and Ringdown in LIGO-Virgo Data from 2009-2010

  The LIGO Scientific Collaboration, the Virgo Collaboration, J. Aasi, J. Abadie, B. P. Abbott, R. Abbott, T. D. Abbott, M. Abernathy, T. Accadia, F. Acernese, [......], M. Yvert, A. Zadrozny, M. Zanolin, J. -P. Zendri, F. Zhang, L. Zhang, C. Zhao, N. Zotov, M. E. Zucker, J. Zweizig
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  ABSTRACT: We report a search for gravitational waves from the inspiral, merger and ringdown of binary black holes (BBH) with total mass between 25 and 100 solar masses, in data taken at the LIGO and Virgo observatories between July 7, 2009 and October 20, 2010. The maximum sensitive distance of the detectors over this period for a (20,20) Msun coalescence was 300 Mpc. No gravitational wave signals were found. We thus report upper limits on the astrophysical coalescence rates of BBH as a function of the component masses for non-spinning components, and also evaluate the dependence of the search sensitivity on component spins aligned with the orbital angular momentum. We find an upper limit at 90% confidence on the coalescence rate of BBH with non-spinning components of mass between 19 and 28 Msun of 3.3 \times 10^-7 mergers /Mpc^3 /yr.
  09/2012;
• Source

  Available from: Reinhard Prix

  Article: Einstein@Home all-sky search for periodic gravitational waves in LIGO S5 data

  J. Aasi, J. Abadie, B. P. Abbott, R. Abbott, T. D. Abbott, M. Abernathy, T. Accadia, F. Acernese, C. Adams, T. Adams, [......], A. Zadrożny, M. Zanolin, J. -P. Zendri, F. Zhang, L. Zhang, C. Zhao, N. Zotov, M. E. Zucker, J. Zweizig, D. P. Anderson
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  ABSTRACT: This paper presents results of an all-sky searches for periodic gravitational waves in the frequency range [50, 1190] Hz and with frequency derivative ranges of [-2 x 10^-9, 1.1 x 10^-10] Hz/s for the fifth LIGO science run (S5). The novelty of the search lies in the use of a non-coherent technique based on the Hough-transform to combine the information from coherent searches on timescales of about one day. Because these searches are very computationally intensive, they have been deployed on the Einstein@Home distributed computing project infrastructure. The search presented here is about a factor 3 more sensitive than the previous Einstein@Home search in early S5 LIGO data. The post-processing has left us with eight surviving candidates. We show that deeper follow-up studies rule each of them out. Hence, since no statistically significant gravitational wave signals have been detected, we report upper limits on the intrinsic gravitational wave amplitude h0. For example, in the 0.5 Hz-wide band at 152.5 Hz, we can exclude the presence of signals with h0 greater than 7.6 x 10^-25 with a 90% confidence level.
  07/2012;
• Article: A First Search for coincident Gravitational Waves and High Energy Neutrinos using LIGO, Virgo and ANTARES data from 2007

  The ANTARES Collaboration, the LIGO Scientific Collaboration, the Virgo Collaboration, S. Adrián-Martínez, I. Al Samarai, A. Albert, M. André, M. Anghinolfi, G. Anton, S. Anvar, [......], M. Yvert, A. Zadroźny, M. Zanolin, J. -P. Zendri, F. Zhang, L. Zhang, C. Zhao, N. Zotov, M. E. Zucker, J. Zweizig
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  ABSTRACT: We present the results of the first search for gravitational wave bursts associated with high energy neutrinos. Together, these messengers could reveal new, hidden sources that are not observed by conventional photon astronomy, particularly at high energy. Our search uses neutrinos detected by the underwater neutrino telescope ANTARES in its 5 line configuration during the period January - September 2007, which coincided with the fifth and first science runs of LIGO and Virgo, respectively. The LIGO-Virgo data were analysed for candidate gravitational-wave signals coincident in time and direction with the neutrino events. No significant coincident events were observed. We place limits on the density of joint high energy neutrino - gravitational wave emission events in the local universe, and compare them with densities of merger and core-collapse events.
  05/2012;
• Article: Search for gravitational waves associated with gamma-ray bursts during LIGO science run 6 and Virgo science runs 2 and 3

  The LIGO Scientific Collaboration, Virgo Collaboration, J. Abadie, B. P. Abbott, R. Abbott, T. D. Abbott, M. Abernathy, T. Accadia, F. Acernese, C. Adams, [......], N. Zotov, M. E. Zucker, J. Zweizig, M. S. Briggs, V. Connaughton, K. C. Hurley, P. A. Jenke, A. von Kienlin, A. Rau, X. -L. Zhang
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  ABSTRACT: We present the results of a search for gravitational waves associated with 154 gamma-ray bursts (GRBs) that were detected by satellite-based gamma-ray experiments in 2009-2010, during the sixth LIGO science run and the second and third Virgo science runs. We perform two distinct searches: a modeled search for coalescences of either two neutron stars or a neutron star and black hole; and a search for generic, unmodeled gravitational-wave bursts. We find no evidence for gravitational-wave counterparts, either with any individual GRB in this sample or with the population as a whole. For all GRBs we place lower bounds on the distance to the progenitor, under the optimistic assumption of a gravitational-wave emission energy of 10^-2 M c^2 at 150 Hz, with a median limit of 17 Mpc. For short hard GRBs we place exclusion distances on binary neutron star and neutron star-black hole progenitors, using astrophysically motivated priors on the source parameters, with median values of 16 Mpc and 28 Mpc respectively. These distance limits, while significantly larger than for a search that is not aided by GRB satellite observations, are not large enough to expect a coincidence with a GRB. However, projecting these exclusions to the sensitivities of Advanced LIGO and Virgo, which should begin operation in 2015, we find that the detection of gravitational waves associated with GRBs will become quite possible.
  05/2012;
• Article: Swift follow-up observations of candidate gravitational-wave transient events

  P. A. Evans, J. K. Fridriksson, N. Gehrels, J. Homan, J. P. Osborne, M. Siegel, A. Beardmore, P. Handbauer, J. Gelbord, J. A. Kennea, [......], M. Yvert, A. Zadrozny, M. Zanolin, J. -P. Zendri, F. Zhang, L. Zhang, C. Zhao, N. Zotov, M. E. Zucker, J. Zweizig
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  ABSTRACT: We present the first multi-wavelength follow-up observations of two candidate gravitational-wave (GW) transient events recorded by LIGO and Virgo in their 2009-2010 science run. The events were selected with low latency by the network of GW detectors and their candidate sky locations were observed by the Swift observatory. Image transient detection was used to analyze the collected electromagnetic data, which were found to be consistent with background. Off-line analysis of the GW data alone has also established that the selected GW events show no evidence of an astrophysical origin; one of them is consistent with background and the other one was a test, part of a "blind injection challenge". With this work we demonstrate the feasibility of rapid follow-ups of GW transients and establish the sensitivity improvement joint electromagnetic and GW observations could bring. This is a first step toward an electromagnetic follow-up program in the regime of routine detections with the advanced GW instruments expected within this decade. In that regime multi-wavelength observations will play a significant role in completing the astrophysical identification of GW sources. We present the methods and results from this first combined analysis and discuss its implications in terms of sensitivity for the present and future instruments.
  05/2012;
• Article: Implementation and testing of the first prompt search for gravitational wave transients with electromagnetic counterparts

  LIGO Scientific Collaboration, Virgo Collaboration, J. Abadie, B. P. Abbott, R. Abbott, T. D. Abbott, M. Abernathy, T. Accadia, F. Acernese, C. Adams, [......], R. Fender, N. Gehrels, A. Klotz, E. O. Ofek, M. Smith, M. Sokolowski, B. W. Stappers, I. Steele, J. Swinbank, R. A. M. J. Wijeres
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  ABSTRACT: Aims: A transient astrophysical event observed in both gravitational wave (GW) and electromagnetic (EM) channels would yield rich scientific rewards. A first program initiating EM follow-ups to possible transient GW events has been developed and exercised by the LIGO and Virgo community in association with several partners. In this paper, we describe and evaluate the methods used to promptly identify and localize GW event candidates and to request images of targeted sky locations. Methods: During two observing periods (Dec. 17, 2009 to Jan. 8, 2010 and Sep. 2 to Oct. 20, 2010), a low-latency analysis pipeline was used to identify GW event candidates and to reconstruct maps of possible sky locations. A catalog of nearby galaxies and Milky Way globular clusters was used to select the most promising sky positions to be imaged, and this directional information was delivered to EM observatories with time lags of about thirty minutes. A Monte Carlo simulation has been used to evaluate the low-latency GW pipeline's ability to reconstruct source positions correctly. Results: For signals near the detection threshold, our low-latency algorithms often localized simulated GW burst signals to tens of square degrees, while neutron star/neutron star inspirals and neutron star/black hole inspirals were localized to a few hundred square degrees. Localization precision improves for moderately stronger signals. The correct sky location of signals well above threshold and originating from nearby galaxies may be observed with ~50% or better probability with a few pointings of wide-field telescopes.
  Astronomy and Astrophysics 03/2012; 539:124. · 4.59 Impact Factor
• Article: Implementation and testing of the first prompt search for gravitational wave transients with electromagnetic counterparts

  LIGO Scientific Collaboration, Virgo Collaboration, J. Abadie, B. P. Abbott, R. Abbott, T. D. Abbott, M. Abernathy, T. Accadia, F. Acernese, C. Adams, [......], R. Fender, N. Gehrels, A. Klotz, E. O. Ofek, M. Smith, M. Sokolowski, B. W. Stappers, I. Steele, J. Swinbank, R. A. M. J. Wijeres
  [show abstract] [hide abstract]
  ABSTRACT: Aims: A transient astrophysical event observed in both gravitational wave (GW) and electromagnetic (EM) channels would yield rich scientific rewards. A first program initiating EM follow-ups to possible transient GW events has been developed and exercised by the LIGO and Virgo community in association with several partners. In this paper, we describe and evaluate the methods used to promptly identify and localize GW event candidates and to request images of targeted sky locations. Methods: During two observing periods (Dec. 17, 2009 to Jan. 8, 2010 and Sep. 2 to Oct. 20, 2010), a low-latency analysis pipeline was used to identify GW event candidates and to reconstruct maps of possible sky locations. A catalog of nearby galaxies and Milky Way globular clusters was used to select the most promising sky positions to be imaged, and this directional information was delivered to EM observatories with time lags of about thirty minutes. A Monte Carlo simulation has been used to evaluate the low-latency GW pipeline's ability to reconstruct source positions correctly. Results: For signals near the detection threshold, our low-latency algorithms often localized simulated GW burst signals to tens of square degrees, while neutron star/neutron star inspirals and neutron star/black hole inspirals were localized to a few hundred square degrees. Localization precision improves for moderately stronger signals. The correct sky location of signals well above threshold and originating from nearby galaxies may be observed with ~50% or better probability with a few pointings of wide-field telescopes.
  Astronomy and Astrophysics 03/2012; 539:124. · 4.59 Impact Factor
• Article: The characterization of Virgo data and its impact on gravitational-wave searches

  J. Aasi, J. Abadie, B. P. Abbott, R. Abbott, T. D. Abbott, M. Abernathy, T. Accadia, F. Acernese, C. Adams, T. Adams, [......], M. Yvert, A. Zadrożny, M. Zanolin, J. -P. Zendri, F. Zhang, L. Zhang, C. Zhao, N. Zotov, M. E. Zucker, J. Zweizig
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  ABSTRACT: Between 2007 and 2010 Virgo collected data in coincidence with the LIGO and GEO gravitational-wave (GW) detectors. These data have been searched for GWs emitted by cataclysmic phenomena in the universe, by non-axisymmetric rotating neutron stars or from a stochastic background in the frequency band of the detectors. The sensitivity of GW searches is limited by noise produced by the detector or its environment. It is therefore crucial to characterize the various noise sources in a GW detector. This paper reviews the Virgo detector noise sources, noise propagation, and conversion mechanisms which were identified in the three first Virgo observing runs. In many cases, these investigations allowed us to mitigate noise sources in the detector, or to selectively flag noise events and discard them from the data. We present examples from the joint LIGO-GEO-Virgo GW searches to show how well noise transients and narrow spectral lines have been identified and excluded from the Virgo data. We also discuss how detector characterization can improve the astrophysical reach of gravitational-wave searches.
  03/2012;
• Source

  Available from: Giancarlo Cella

  Article: All-sky search for gravitational-wave bursts in the second joint LIGO-Virgo run

  the LIGO Scientific Collaboration, the Virgo Collaboration, J. Abadie, B. P. Abbott, R. Abbott, T. D. Abbott, M. Abernathy, T. Accadia, F. Acernese, C. Adams, [......], A. Zadrozny, M. Zanolin, J. -P. Zendri, F. Zhang, L. Zhang, W. Zhang, C. Zhao, N. Zotov, M. E. Zucker, J. Zweizig
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  ABSTRACT: We present results from a search for gravitational-wave bursts in the data collected by the LIGO and Virgo detectors between July 7, 2009 and October 20, 2010: data are analyzed when at least two of the three LIGO-Virgo detectors are in coincident operation, with a total observation time of 207 days. The analysis searches for transients of duration < 1 s over the frequency band 64-5000 Hz, without other assumptions on the signal waveform, polarization, direction or occurrence time. All identified events are consistent with the expected accidental background. We set frequentist upper limits on the rate of gravitational-wave bursts by combining this search with the previous LIGO-Virgo search on the data collected between November 2005 and October 2007. The upper limit on the rate of strong gravitational-wave bursts at the Earth is 1.3 events per year at 90% confidence. We also present upper limits on source rate density per year and Mpc^3 for sample populations of standard-candle sources. As in the previous joint run, typical sensitivities of the search in terms of the root-sum-squared strain amplitude for these waveforms lie in the range 5 10^-22 Hz^-1/2 to 1 10^-20 Hz^-1/2. The combination of the two joint runs entails the most sensitive all-sky search for generic gravitational-wave bursts and synthesizes the results achieved by the initial generation of interferometric detectors.
  02/2012;
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  Available from: Giancarlo Cella

  Article: Search for Gravitational Waves from Intermediate Mass Binary Black Holes

  the LIGO Scientific Collaboration, the Virgo Collaboration, J. Abadie, B. P. Abbott, R. Abbott, T. D. Abbott, M. Abernathy, T. Accadia, F. Acernese, C. Adams, [......], A. Zadrozny, M. Zanolin, J. -P. Zendri, F. Zhang, L. Zhang, W. Zhang, C. Zhao, N. Zotov, M. E. Zucker, J. Zweizig
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  ABSTRACT: We present the results of a weakly modeled burst search for gravitational waves from mergers of non-spinning intermediate mass black holes (IMBH) in the total mass range 100--450 solar masses and with the component mass ratios between 1:1 and 4:1. The search was conducted on data collected by the LIGO and Virgo detectors between November of 2005 and October of 2007. No plausible signals were observed by the search which constrains the astrophysical rates of the IMBH mergers as a function of the component masses. In the most efficiently detected bin centered on 88+88 solar masses, for non-spinning sources, the rate density upper limit is 0.13 per Mpc^3 per Myr at the 90% confidence level.
  01/2012;
• Source

  Available from: Saumitra Mukherjee

  Article: Implications For The Origin Of GRB 051103 From LIGO Observations

  The LIGO Scientific Collaboration, J. Abadie, B. P. Abbott, T. D. Abbott, R. Abbott, M. Abernathy, C. Adams, R. Adhikari, C. Affeldt, P. Ajith, [......], L. Zhang, Z. Zhang, C. Zhao, N. Zotov, M. E. Zucker, J. Zweizig, M. A. Bizouard, A. Dietz, G. M. Guidi, M. Was
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  ABSTRACT: We present the results of a LIGO search for gravitational waves (GWs) associated with GRB 051103, a short-duration hard-spectrum gamma-ray burst (GRB) whose electromagnetically determined sky position is coincident with the spiral galaxy M81, which is 3.6 Mpc from Earth. Possible progenitors for short-hard GRBs include compact object mergers and soft gamma repeater (SGR) giant flares. A merger progenitor would produce a characteristic GW signal that should be detectable at the distance of M81, while GW emission from an SGR is not expected to be detectable at that distance. We found no evidence of a GW signal associated with GRB 051103. Assuming weakly beamed gamma-ray emission with a jet semi-angle of 30 deg we exclude a binary neutron star merger in M81 as the progenitor with a confidence of 98%. Neutron star-black hole mergers are excluded with > 99% confidence. If the event occurred in M81 our findings support the the hypothesis that GRB 051103 was due to an SGR giant flare, making it the most distant extragalactic magnetar observed to date.
  01/2012;
• Article: Publisher's Note: Search for gravitational waves from binary black hole inspiral, merger, and ringdown (vol 83, 122005, 2011)

  J. Abadie, B. P. Abbott, R. Abbott, M. Abernathy, T. Accadia, F. Acernese, C. Adams, R. Adhikari, P. Ajith, B. Allen, [......], S. Yoshida, P. Yu, M. Yvert, M. Zanolin, L. Zhang, Z. Zhang, C. Zhao, N. Zotov, M. E. Zucker, J. Zweizig
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  ABSTRACT: Abadie, J. Abbott, B. P. Abbott, R. Abernathy, M. Accadia, T. Acernese, F. Adams, C. Adhikari, R. Ajith, P. Allen, B. Allen, G. S. Ceron, E. Amador Amin, R. S. Anderson, S. B. Anderson, W. G. Antonucci, F. Arain, M. A. Araya, M. C. Aronsson, M. Aso, Y. Aston, S. M. Astone, P. Atkinson, D. Aufmuth, P. Aulbert, C. Babak, S. Baker, P. Ballardin, G. Ballinger, T. Ballmer, S. Barker, D. Barnum, S. Barone, F. Barr, B. Barriga, P. Barsotti, L. Barsuglia, M. Barton, M. A. Bartos, I. Bassiri, R. Bastarrika, M. Bauchrowitz, J. Bauer, Th. S. Behnke, B. Beker, M. G. Belletoile, A. Benacquista, M. Bertolini, A. Betzwieser, J. Beveridge, N. Beyersdorf, P. T. Bilenko, I. A. Billingsley, G. Birch, J. Birindelli, S. Biswas, R. Bitossi, M. Bizouard, M. A. Black, E. Blackburn, J. K. Blackburn, L. Blair, D. Bland, B. Blom, M. Boccara, C. Bock, O. Bodiya, T. P. Bondarescu, R. Bondu, F. Bonelli, L. Bonnand, R. Bork, R. Born, M. Boschi, V. Bose, S. Bosi, L. Bouhou, B. Boyle, M. Braccini, S. Bradaschia, C. Brady, P. R. Bragin
  Physical Review D 01/2012; 85. · 4.56 Impact Factor
• Article: Publisher's Note: Search for gravitational waves from compact binary coalescence in LIGO and Virgo data from S5 and VSR1 (vol 82, 102001, 2010)

  J. Abadie, B. P. Abbott, R. Abbott, M. Abernathy, T. Accadia, F. Acernese, C. Adams, R. Adhikari, P. Ajith, B. Allen, [......], S. Yoshida, P. P. Yu, M. Yvert, M. Zanolin, L. Zhang, Z. Zhang, C. Zhao, N. Zotov, M. E. Zucker, J. Zweizig
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  ABSTRACT: Abadie, J. Abbott, B. P. Abbott, R. Abernathy, M. Accadia, T. Acernese, F. Adams, C. Adhikari, R. Ajith, P. Allen, B. Allen, G. Ceron, E. Amador Amin, R. S. Anderson, S. B. Anderson, W. G. Antonucci, F. Arain, M. A. Araya, M. Aronsson, M. Arun, K. G. Aso, Y. Aston, S. Astone, P. Atkinson, D. E. Aufmuth, P. Aulbert, C. Babak, S. Baker, P. Ballardin, G. Ballinger, T. Ballmer, S. Barker, D. Barnum, S. Barone, F. Barr, B. Barriga, P. Barsotti, L. Barsuglia, M. Barton, M. A. Bartos, I. Bassiri, R. Bastarrika, M. Bauchrowitz, J. Bauer, Th. S. Behnke, B. Beker, M. G. Belletoile, A. Benacquista, M. Bertolini, A. Betzwieser, J. Beveridge, N. Beyersdorf, P. T. Bigotta, S. Bilenko, I. A. Billingsley, G. Birch, J. Birindelli, S. Biswas, R. Bitossi, M. Bizouard, M. A. Black, E. Blackburn, J. K. Blackburn, L. Blair, D. Bland, B. Blom, M. Boccara, C. Bock, O. Bodiya, T. P. Bondarescu, R. Bondu, F. Bonelli, L. Bonnand, R. Bork, R. Born, M. Bose, S. Bosi, L. Bouhou, B. Boyle, M. Braccini, S. Bradaschia, C. Brady, P. R.
  Physical Review D 01/2012; 85. · 4.56 Impact Factor
• Article: Publisher's Note: Search for gravitational waves from compact binary coalescence in LIGO and Virgo data from S5 and VSR1 (vol 82, 102001, 2010)

  J. Abadie, B. P. Abbott, R. Abbott, M. Abernathy, T. Accadia, F. Acernese, C. Adams, R. Adhikari, P. Ajith, B. Allen, [......], S. Yoshida, P. P. Yu, M. Yvert, M. Zanolin, L. Zhang, Z. Zhang, C. Zhao, N. Zotov, M. E. Zucker, J. Zweizig
  [show abstract] [hide abstract]
  ABSTRACT: Abadie, J. Abbott, B. P. Abbott, R. Abernathy, M. Accadia, T. Acernese, F. Adams, C. Adhikari, R. Ajith, P. Allen, B. Allen, G. Ceron, E. Amador Amin, R. S. Anderson, S. B. Anderson, W. G. Antonucci, F. Arain, M. A. Araya, M. Aronsson, M. Arun, K. G. Aso, Y. Aston, S. Astone, P. Atkinson, D. E. Aufmuth, P. Aulbert, C. Babak, S. Baker, P. Ballardin, G. Ballinger, T. Ballmer, S. Barker, D. Barnum, S. Barone, F. Barr, B. Barriga, P. Barsotti, L. Barsuglia, M. Barton, M. A. Bartos, I. Bassiri, R. Bastarrika, M. Bauchrowitz, J. Bauer, Th. S. Behnke, B. Beker, M. G. Belletoile, A. Benacquista, M. Bertolini, A. Betzwieser, J. Beveridge, N. Beyersdorf, P. T. Bigotta, S. Bilenko, I. A. Billingsley, G. Birch, J. Birindelli, S. Biswas, R. Bitossi, M. Bizouard, M. A. Black, E. Blackburn, J. K. Blackburn, L. Blair, D. Bland, B. Blom, M. Boccara, C. Bock, O. Bodiya, T. P. Bondarescu, R. Bondu, F. Bonelli, L. Bonnand, R. Bork, R. Born, M. Bose, S. Bosi, L. Bouhou, B. Boyle, M. Braccini, S. Bradaschia, C. Brady, P. R.
  Physical Review D 01/2012; 85. · 4.56 Impact Factor
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  Available from: Giancarlo Cella

  Article: Directional limits on persistent gravitational waves using LIGO S5 science data.

  J Abadie, B P Abbott, R Abbott, M Abernathy, T Accadia, F Acernese, C Adams, R Adhikari, P Ajith, B Allen, [......], S Yoshida, P Yu, M Yvert, M Zanolin, L Zhang, Z Zhang, C Zhao, N Zotov, M E Zucker, J Zweizig
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  ABSTRACT: The gravitational-wave (GW) sky may include nearby pointlike sources as well as stochastic backgrounds. We perform two directional searches for persistent GWs using data from the LIGO S5 science run: one optimized for pointlike sources and one for arbitrary extended sources. Finding no evidence to support the detection of GWs, we present 90% confidence level (C.L.) upper-limit maps of GW strain power with typical values between 2-20×10(-50)  strain(2) Hz(-1) and 5-35×10(-49)  strain(2) Hz(-1) sr(-1) for pointlike and extended sources, respectively. The latter result is the first of its kind. We also set 90% C.L. limits on the narrow-band root-mean-square GW strain from interesting targets including Sco X-1, SN 1987A and the Galactic center as low as ≈7×10(-25) in the most sensitive frequency range near 160 Hz.
  Physical Review Letters 12/2011; 107(27):271102. · 7.37 Impact Factor
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  Available from: Giancarlo Cella

  Article: Upper limits on a stochastic gravitational-wave background using LIGO and Virgo interferometers at 600-1000 Hz

  J. Abadie, B. P. Abbott, R. Abbott, T. D. Abbott, M. Abernathy, T. Accadia, F. Acernese, C. Adams, R. Adhikari, C. Affeldt, [......], A. Zadroźny, M. Zanolin, J. -P. Zendri, F. Zhang, L. Zhang, W. Zhang, C. Zhao, N. Zotov, M. E. Zucker, J. Zweizig
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  ABSTRACT: A stochastic background of gravitational waves is expected to arise from a superposition of many incoherent sources of gravitational waves, of either cosmological or astrophysical origin. This background is a target for the current generation of ground-based detectors. In this article we present the first joint search for a stochastic background using data from the LIGO and Virgo interferometers. In a frequency band of 600-1000 Hz, we obtained a 95% upper limit on the amplitude of $\Omega_{\rm GW}(f) = \Omega_3 (f/900 \mathrm{Hz})^3$, of $\Omega_3 < 0.33$, assuming a value of the Hubble parameter of $h_{100}=0.72$. These new limits are a factor of seven better than the previous best in this frequency band.
  12/2011;
• Source

  Available from: Saumitra Mukherjee

  Article: Search for Gravitational Waves from Low Mass Compact Binary Coalescence in LIGO's Sixth Science Run and Virgo's Science Runs 2 and 3

  the LIGO Scientific Collaboration, the Virgo Collaboration, J. Abadie, B. P. Abbott, R. Abbott, T. D. Abbott, M. Abernathy, T. Accadia, F. Acernese, C. Adams, [......], M. Zanolin, J. -P. Zendri, F. Zhang, L. Zhang, W. Zhang, Z. Zhang, C. Zhao, N. Zotov, M. E. Zucker, J. Zweizig
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  ABSTRACT: We report on a search for gravitational waves from coalescing compact binaries using LIGO and Virgo observations between July 7, 2009 and October 20, 2010. We searched for signals from binaries with total mass between 2 and 25 solar masses; this includes binary neutron stars, binary black holes, and binaries consisting of a black hole and neutron star. The detectors were sensitive to systems up to 40 Mpc distant for binary neutron stars, and further for higher mass systems. No gravitational-wave signals were detected. We report upper limits on the rate of compact binary coalescence as a function of total mass, including the results from previous LIGO and Virgo observations. The cumulative 90%-confidence rate upper limits of the binary coalescence of binary neutron star, neutron star- black hole and binary black hole systems are 1.3 x 10^{-4}, 3.1 x 10^{-5} and 6.4 x 10^{-6} Mpc^{-3}yr^{-1}, respectively. These upper limits are up to a factor 1.4 lower than previously derived limits. We also report on results from a blind injection challenge.
  11/2011;