LIGO Scientific Collaboration

Loyola University Maryland, Baltimore, Maryland, United States

Are you LIGO Scientific Collaboration?

Claim your profile

Publications (22)55.36 Total impact

  • LIGO Collaboration, Virgo Collaboration
  • Source
    LIGO Scientific Collaboration, Virgo Collaboration
    [Show abstract] [Hide abstract]
    ABSTRACT: We report on an all--sky search for periodic gravitational waves in the frequency range $\mathrm{50-1000\,Hz}$ with the first derivative of frequency in the range $-8.9 \times 10^{-10}$~Hz/s to zero in two years of data collected during LIGO's fifth science run. Our results employ a Hough transform technique, introducing a $\chi^2$ test and analysis of coincidences between the signal levels in years 1 and 2 of observations that offers a significant improvement in the product of strain sensitivity with compute cycles per data sample compared to previously published searches. Since our search yields no surviving candidates, we present results taking the form of frequency dependent, 95$\%$ confidence upper limits on the strain amplitude $h_0$. The most stringent upper limit from year 1 is $1.0\times 10^{-24}$ in the $\mathrm{158.00-158.25\,Hz}$ band. In year 2, the most stringent upper limit is $\mathrm{8.9\times10^{-25}}$ in the $\mathrm{146.50-146.75\,Hz}$ band. This improved detection pipeline, which is computationally efficient by at least two orders of magnitude better than our flagship Einstein$@$Home search, will be important for "quick-look" searches in the Advanced LIGO and Virgo detector era.
    11/2013;
  • [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. · 5.08 Impact Factor
  • Source
    [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. · 5.08 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Around the globe several observatories are seeking the first direct detection of gravitational waves (GWs). These waves are predicted by Einstein's general theory of relativity and are generated, for example, by black-hole binary systems. Present GW detectors are Michelson-type kilometre-scale laser interferometers measuring the distance changes between mirrors suspended in vacuum. The sensitivity of these detectors at frequencies above several hundred hertz is limited by the vacuum (zero-point) fluctuations of the electromagnetic field. A quantum technology--the injection of squeezed light--offers a solution to this problem. Here we demonstrate the squeezed-light enhancement of GEO600, which will be the GW observatory operated by the LIGO Scientific Collaboration in its search for GWs for the next 3-4 years. GEO600 now operates with its best ever sensitivity, which proves the usefulness of quantum entanglement and the qualification of squeezed light as a key technology for future GW astronomy.
    Nature Physics 12/2011; 7:962-965. · 19.35 Impact Factor
  • Source
    LIGO Scientific Collaboration, Virgo Collaboration, Michael W. Coughlin
    [Show abstract] [Hide abstract]
    ABSTRACT: An important goal for LIGO (the Laser Interferometer Gravitational-Wave Observatory) and Virgo is to find periodic sources of gravitational waves. The LIGO and Virgo detectors are sensitive to a variety of noise of non-astrophysical origin, such as instrumental artifacts and environmental disturbances. These artifacts make it difficult to know when a signal is due to a gravitational wave or noise. A continuous wave search algorithm, Fscan, and the calculation of the coherence between the gravitational wave channels and auxiliary channels has been developed to identify the source of noise lines. The programs analyze data from the gravitational wave channels as well as environmental sensors, searching for significant lines that appear in coincidence (using various thresholds and frequency windows) in the gravitational wave channel as well the environmental monitors. By this method, the source of powerful signals at specific frequencies in the gravitational wave channel caused by noise can be determined. Examples from LIGO's sixth science run, S6, and Virgo' second scientific run, VSR2, are presented.
    Journal of Physics: Conference Series. 09/2011; 243(1).
  • Source
    LIGO Scientific Collaboration, Virgo Collaboration, Michael W. Coughlin
    [Show abstract] [Hide abstract]
    ABSTRACT: The LIGO and Virgo detectors are sensitive to a variety of noise sources, such as instrumental artifacts and environmental disturbances. The Stochastic Transient Analysis Multi-detector Pipeline (STAMP) has been developed to search for long-duration (t$\gtrsim$1s) gravitational-wave (GW) signals. This pipeline can also be used to identify environmental noise transients. Here we present an algorithm to determine when long-duration noise sources couple into the interferometers, as well as identify what these noise sources are. We analyze the cross-power between a GW strain channel and an environmental sensor, using pattern recognition tools to identify statistically significant structure in cross-power time-frequency maps. We identify interferometer noise from airplanes, helicopters, thunderstorms and other sources. Examples from LIGO's sixth science run, S6, and Virgo's third scientific run, VSR3, are presented.
    Classical and Quantum Gravity 08/2011; 28(23). · 3.56 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: The Laser Interferometer Gravitational Wave Observatory (LIGO) is a network of three detectors built to detect local perturbations in the space-time metric from astrophysical sources. These detectors, two in Hanford, WA and one in Livingston, LA, are power-recycled Fabry-Perot Michelson interferometers. In their fifth science run (S5), between November 2005 and October 2007, these detectors accumulated one year of triple coincident data while operating at their designed sensitivity. In this paper, we describe the calibration of the instruments in the S5 data set, including measurement techniques and uncertainty estimation. Comment: 49 pages, 23 figures
    07/2010;
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: We present a search for periodic gravitational waves from the neutron star in the supernova remnant Cassiopeia A. The search coherently analyzes data in a 12 day interval taken from the fifth science run of the Laser Interferometer Gravitational-Wave Observatory. It searches gravitational-wave frequencies from 100 to 300 Hz and covers a wide range of first and second frequency derivatives appropriate for the age of the remnant and for different spin-down mechanisms. No gravitational-wave signal was detected. Within the range of search frequencies, we set 95% confidence upper limits of (0.7-1.2) × 10^-24 on the intrinsic gravitational-wave strain, (0.4-4) × 10^-4 on the equatorial ellipticity of the neutron star, and 0.005-0.14 on the amplitude of r-mode oscillations of the neutron star. These direct upper limits beat indirect limits derived from energy conservation and enter the range of theoretical predictions involving crystalline exotic matter or runaway r-modes. This paper is also the first gravitational-wave search to present upper limits on the r-mode amplitude.
    The Astrophysical Journal 06/2010; 722(2):1504. · 6.73 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: We present an up-to-date, comprehensive summary of the rates for all types of compact binary coalescence sources detectable by the Initial and Advanced versions of the ground-based gravitational-wave detectors LIGO and Virgo. Astrophysical estimates for compact-binary coalescence rates depend on a number of assumptions and unknown model parameters, and are still uncertain. The most confident among these estimates are the rate predictions for coalescing binary neutron stars which are based on extrapolations from observed binary pulsars in our Galaxy. These yield a likely coalescence rate of 100 per Myr per Milky Way Equivalent Galaxy (MWEG), although the rate could plausibly range from 1 per Myr per MWEG to 1000 per Myr per MWEG. We convert coalescence rates into detection rates based on data from the LIGO S5 and Virgo VSR2 science runs and projected sensitivities for our Advanced detectors. Using the detector sensitivities derived from these data, we find a likely detection rate of 0.02 per year for Initial LIGO-Virgo interferometers, with a plausible range between 0.0002 and 0.2 per year. The likely binary neutron-star detection rate for the Advanced LIGO-Virgo network increases to 40 events per year, with a range between 0.4 and 400 per year.
    03/2010;
  • Peter S. Shawhan, LIGO Scientific Collaboration, Virgo Collaboration
    [Show abstract] [Hide abstract]
    ABSTRACT: The large gravitational-wave detectors in the U.S. and Europe are now collecting data and searching for the gravitational signatures of compact binary mergers, stellar core collapse, black hole creation, and other highly energetic astrophysical events. One part of this effort is an attempt to Locate and Observe Optical Counterparts to Unmodeled Pulses of gravitational waves, by enlisting wide-field optical telescopes to promptly capture images of the sky positions reconstructed for gravitational-wave signal candidates. A transient optical counterpart, if detected, could help confirm a signal candidate as a real event and would yield valuable information about the progenitor and the astrophysics of the event. This poster will describe the methods and current operation of the LOOC-UP project. This work is supported by the National Science Foundation and other funding agencies worldwide.
    12/2009; 42:230.
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: We present the results of a search for gravitational-wave bursts associated with 137 gamma-ray bursts (GRBs) that were detected by satellite-based gamma-ray experiments during the fifth LIGO science run and first Virgo science run. The data used in this analysis were collected from 2005 November 4 to 2007 October 1, and most of the GRB triggers were from the Swift satellite. The search uses a coherent network analysis method that takes into account the different locations and orientations of the interferometers at the three LIGO-Virgo sites. We find no evidence for gravitational-wave burst signals associated with this sample of GRBs. Using simulated short-duration (<1 s) waveforms, we set upper limits on the amplitude of gravitational waves associated with each GRB. We also place lower bounds on the distance to each GRB under the assumption of a fixed energy emission in gravitational waves, with typical limits of D ~ 15 Mpc (E_GW^iso / 0.01 M_o c^2)^1/2 for emission at frequencies around 150 Hz, where the LIGO-Virgo detector network has best sensitivity. We present astrophysical interpretations and implications of these results, and prospects for corresponding searches during future LIGO-Virgo runs.
    The Astrophysical Journal 08/2009; · 6.73 Impact Factor
  • Source
    LIGO Scientific Collaboration, B. P. Abbott
    [Show abstract] [Hide abstract]
    ABSTRACT: We present the results obtained from an all-sky search for gravitational-wave (GW) bursts in the 64-2000 Hz frequency range in data collected by the LIGO detectors during the first year (November 2005 - November 2006) of their fifth science run. The total analyzed livetime was 268.6 days. Multiple hierarchical data analysis methods were invoked in this search. The overall sensitivity expressed in terms of the root-sum-square (rss) strain amplitude h_{rss} for gravitational-wave bursts with various morphologies was in the range of 6 times 10^{-22} Hz^{-1/2} to a few times 10^{-21} Hz^{-1/2}. No GW signals were observed and a frequentist upper limit of 3.6 events per year on the rate of strong GW bursts was placed at the 90% confidence level. As in our previous searches, we also combined this rate limit with the detection efficiency for selected waveform morphologies to obtain event rate versus strength exclusion curves. In sensitivity, these exclusion curves are the most stringent to date. Comment: v3: various figure and text edits; submitted to PRD; 26 pages
    04/2009;
  • H Grote, LIGO Scientific Collaboration
    [Show abstract] [Hide abstract]
    ABSTRACT: The German-British laser-interferometric gravitational wave detector GEO 600 is in its 13th year of operation since its first lock in 2001. After participating in science runs with other first generation detectors, GEO\,600 has continued collecting data as an astrowatch instrument with a duty cycle of 62% during the time when the other detectors have gone offline to undergo substantial upgrades. Less invasive upgrades to demonstrate advanced technologies and improve the GEO 600 sensitivity at high frequencies as part of the GEO-HF program have additionally been carried out in parallel to data taking. We report briefly on the status of GEO 600.
    Classical and Quantum Gravity 01/2008; 25(11):114043. · 3.56 Impact Factor
  • Source
    LIGO Scientific Collaboration, TAMA Collaboration
    [Show abstract] [Hide abstract]
    ABSTRACT: We search for coincident gravitational wave signals from inspiralling neutron star binaries using LIGO and TAMA300 data taken during early 2003. Using a simple trigger exchange method, we perform an inter-collaboration coincidence search during times when TAMA300 and only one of the LIGO sites were operational. We find no evidence of any gravitational wave signals. We place an observational upper limit on the rate of binary neutron star coalescence with component masses between 1 and 3 M_sun of 49 per year per Milky Way equivalent galaxy at a 90% confidence level. The methods developed during this search will find application in future network inspiral analyses.
    01/2006;
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: We search for coincident gravitational wave signals from inspiralling neutron star binaries using LIGO and TAMA300 data taken during early 2003. Using a simple trigger exchange method, we perform an intercollaboration coincidence search during times when TAMA300 and only one of the LIGO sites were operational. We find no evidence of any gravitational wave signals. We place an observational upper limit on the rate of binary neutron star coalescence with component masses between 1 and 3M⊙ of 49 per year per Milky Way equivalent galaxy at a 90% confidence level. The methods developed during this search will find application in future network inspiral analyses.
    Physical Review D 01/2006; 73:102002. · 4.69 Impact Factor
  • Source
    Proceedings of the The Tenth Marcel Grossmann Meeting on Recent Developments in Theoretical and Experimental General Relativity, Gravitation and Relavistic Field Theories : proceedings of the MG10 meeting held at Brazilian Center for Research Physics (CBPF), Rio de Janeiro, Brazil, 20 - 26 July 2003; 01/2005
  • Proceedings of the The Tenth Marcel Grossmann Meeting on Recent Developments in Theoretical and Experimental General Relativity, Gravitation and Relavistic Field Theories : proceedings of the MG10 meeting held at Brazilian Center for Research Physics (CBPF), Rio de Janeiro, Brazil, 20 - 26 July 2003; 01/2005
  • Source
    Gabriela González, LIGO Scientific Collaboration
    [Show abstract] [Hide abstract]
    ABSTRACT: Several interferometric gravitational wave detectors around the world are now starting to achieve better sensitivity to gravitational waves than ever before. We describe the prospects these detectors offer for physics and astronomy and review the rapid progress and the present status of the detectors’ sensitivities. We also report the progress made by the LIGO Scientific Collaboration in analysing the data produced by the LIGO and GEO detectors during the Collaboration’s Science Runs.
    Pramana 10/2004; 63(4):663-672. · 0.56 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: A search for periodic gravitational waves, from sources such as isolated rapidly-spinning neutron stars, was carried out using 510 hours of data from the fourth LIGO science run (S4). The search was for quasi-monochromatic waves in the frequency range from 50 Hz to 1500 Hz, with a linear frequency drift f-dot (measured at the solar system barycenter) in the range -f/tau < f-dot < 0.1 f/tau, where the minimum spin-down age tau was 1000 years for signals below 300 Hz and 10000 years above 300 Hz. The main computational work of the search was distributed over approximately 100000 computers volunteered by the general public. This large computing power allowed the use of a relatively long coherent integration time of 30 hours, despite the large parameter space searched. No statistically significant signals were found. The sensitivity of the search is estimated, along with the fraction of parameter space that was vetoed because of contamination by instrumental artifacts. In the 100 Hz to 200 Hz band, more than 90% of sources with dimensionless gravitational wave strain amplitude greater than 1e-23 would have been detected.
    Physical Review D, v.79 (2009).