8 research outputs found
Noise from scattered light in Virgo's second science run data
No full textVirgo is one of the large, ground-based interferometers aimed at detecting gravitational waves. One of the technical problems limiting its sensitivity is caused by light in the output beams which is backscattered by seismically excited surfaces and couples back into the main beam of the interferometer. The resulting noise was thoroughly studied, measured and mitigated before Virgo's second science run (VSR2). The residual noise during VSR2, which increases in periods with a large microseism activity, is accurately predicted by the theoretical model. The scattered light has been associated with transient events in the gravitational-wave signal of the interferometer
Joint searches for gravitational waves and high-energy neutrinos
No full textMany of the astrophysical sources and violent phenomena observed in our Universe are potential joint emitters of gravitational waves and high-energy cosmic radiation, in the form of photons, hadrons, and also neutrinos. This has triggered a collaborative analysis project between gravitational wave detectors and high-energy neutrino telescopes. In this article, we review some of the motivations for having pursuing science jointly and present the effort’s status
Open questions in astrophysically triggered gravitational wave searches
No full textSources of gravitational waves are often expected to also be observable through several other messengers, such as gamma rays, X-rays, optical, radio, and/or neutrino emission. Some of these channels are already being used in searches for gravitational waves with the LIGO-GEO600-Virgo interferometer network, and others are currently being incorporated into new searches. Astrophysical targets include gamma-ray bursts, soft-gamma repeaters, supernovae, and glitching pulsars. The simultaneous observation of electromagnetic or neutrino emission could be a crucial aspect for the first direct detection of gravitational waves. Information on the progenitor, such as trigger time, direction and expected frequency range, can enhance our ability to identify gravitational wave signatures with amplitudes close to the noise floor of the detector. Furthermore, combining gravitational waves with electromagnetic and neutrino observations will enable the extraction of scientific insight that was hidden from us before. The paper discusses the status of transient multimessenger detection efforts as well as intriguing questions that might be resolved in the future by advanced and third generation gravitational wave detector
Virgo calibration and reconstruction of the gravitational wave strain during VSR1
Get PDFVirgo is a kilometer-length interferometer for gravitational waves detection located near Pisa. Its first science run, VSR1, occured from May to October 2007. The aims of the calibration are to measure the detector sensitivity and to reconstruct the time series of the gravitational wave strain h(t). The absolute length calibration is based on an original non-linear reconstruction of the differential arm length variations in free swinging Michelson configurations. It uses the laser wavelength as length standard. This method is used to calibrate the frequency dependent response of the Virgo mirror actuators and derive the detector in-loop response and sensitivity within ~5%. The principle of the strain reconstruction is highlighted and the h(t) systematic errors are estimated. A photon calibrator is used to check the sign of h(t). The reconstructed h(t) during VSR1 is valid from 10 Hz up to 10 kHz with systematic errors estimated to 6% in amplitude. The phase error is estimated to be 70 mrad below 1.9 kHz and 6 micro-seconds above
Predictions for the rates of compact binary coalescences observable by ground-based gravitational-wave detectors
Get PDFWe 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. Themost 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 Myr(-1) per Milky Way Equivalent Galaxy (MWEG), although the rate could plausibly range from 1 Myr(-1) MWEG(-1) to 1000 Myr(-1) MWEG(-1) (Kalogera et al 2004 Astrophys. J. 601 L179; Kalogera et al 2004 Astrophys. J. 614 L137 ( erratum)). 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 2 x 10(-4) 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
Tools for noise characterization in Virgo
Get PDFInternational audienceSeveral software tools were used to perform on-line and of-line noise analysis as a support to commissioning activities, to monitor the rate of glitches, the occurrence of non stationary noise, the presence of environmental contamination, the behavior of narrow spectral features and the coherence with auxiliary channels. We report about the use of these tools to study the main sources of identified noise: broadband, spectral lines and glitches. Plans for the upgrade of the tools will be presented, for example for lines identification purpose to let the scientists in control room do noise characterization in an easier way
Search for gravitational waves from compact binary coalescence in LIGO and Virgo data from S5 and VSR1
Get PDFWe report the results of the first search for gravitational waves from compact binary coalescence using data from the Laser Interferometer Gravitational-Wave Observatory and Virgo detectors. Five months of data were collected during the Laser Interferometer Gravitational-Wave Observatory’s S5 and Virgo’s VSR1 science runs. The search focused on signals from binary mergers with a total mass between 2 and 35M⊙. No gravitational waves are identified. The cumulative 90%-confidence upper limits on the rate of compact binary coalescence are calculated for nonspinning binary neutron stars, black hole-neutron star systems, and binary black holes to be 8.7×10-3 yr-1 L10-1, 2.2×10-3 yr-1 L10-1, and 4.4×10-4 yr-1 L10-1, respectively, where L10 is 1010 times the blue solar luminosity. These upper limits are compared with astrophysical expectations.National Science Foundation (U.S.)United States. National Aeronautics and Space AdministrationCarnegie TrustLeverhulme TrustDavid & Lucile Packard FoundationAlfred P. Sloan FoundationResearch Corporatio
Status and perspectives of the Virgo gravitational wave detector
Get PDFInternational audienceVirgo is designed to detect gravitational waves of both astrophysical and cosmological origin in the frequency range from a few Hz to a few kHz. After the end of the first science run, partially overlapped with the LIGO fifth science run, the detector underwent several upgrades to improve its sensitivity. The second Virgo science run started at the beginning of July 2009 in coincidence with LIGO. A further upgrade is planned at beginning of 2010 with the installation of new suspensions for the test masses and of new mirrors. This will lead to a considerable improvement in the sensitivity and represents an intermediate step toward the development of the advanced detectors
