752 research outputs found
Virgo an interferometer for gravitational wave detection
No full textGravitational waves propagating from rapidly accelerating star masses can be detected by means of interferometric techniques. The Virgo detector is a Michelson interferometer, with two 3 km long Fabry-Perot cavities, that is going to be built in the countryside of Pisa (Italy). Principles of interferometric gravitational wave detection, and the main noise sources in the Virgo apparatus are treated. The Virgo optical scheme and its main components are also described. Finally, an overview on the status of works at the Virgo site is presented. © 2000 by the American College of Cardiology
Search for subsolar-mass black hole binaries in the second part of Advanced LIGO's and Advanced Virgo's third observing run
No full textWe describe a search for gravitational waves from compact binaries with at least one component with mass 0.2-1.0 M-circle dot and mass ratio q >= 0.1 in Advanced Laser Interferometer Gravitational-Wave Observatory (LIGO) and Advanced Virgo data collected between 2019 November 1, 15:00 UTC and 2020 March 27, 17:00 UTC. No signals were detected. The most significant candidate has a false alarm rate of 0.2 yr(-1). We estimate the sensitivity of our search over the entirety of Advanced LIGO's and Advanced Virgo's third observing run, and present the most stringent limits to date on the merger rate of binary black holes with at least one subsolar-mass component. We use the upper limits to constrain two fiducial scenarios that could produce subsolar-mass black holes: primordial black holes (PBH) and a model of dissipative dark matter. The PBH model uses recent prescriptions for the merger rate of PBH binaries that include a rate suppression factor to effectively account for PBH early binary disruptions. If the PBHs are monochromatically distributed, we can exclude a dark matter fraction in PBHs f(PBH) greater than or similar to 0.6 (at 90 per cent confidence) in the probed subsolar-mass range. However, if we allow for broad PBH mass distributions, we are unable to rule out f(PBH) = 1. For the dissipative model, where the dark matter has chemistry that allows a small fraction to cool and collapse into black holes, we find an upper bound f(DBH) < 10(-5) on the fraction of atomic dark matter collapsed into black holes
Status report of the low frequency facility experiment, Virgo R&D
No full textThe low frequency facility, a Virgo R&D experiment, is composed by a Fabry–Perot cavity attached and controlled by the Virgo suspension; the goal is to measure the thermal noise of the apparatus above 10 Hz, with a displacement sensitivity as high as 10−18 m. Since September 2001 the apparatus, located inside the INFN-Pisa experimental area, has been completely built and put into operation. Vacuum facilities and the control loops have been set up. Transfer functions, necessary to control the cavity, absolute test mass displacement and the first demonstration of the cavity locking are reported
High sensitivity rotation measurements with a mid-size laser gyroscope
No full textAn high sensitivity laser gyroscope is presented operating in a square cavity of side length of the order of 1 m with a measured sensitivity limit at the level of 2 10-9(rad/s)/ √Hz. We report on the active stabilization of the laser optical frequency which is mainly driven by the environmental thermal fluctuations and the experimental results obtained with the active stabilization system are given. Finally the applications of this gyrolaser as an high-sensitive tilt-meter in Virgo, the large-frame interferometer for gravitational waves detection, are discussed
Monitoring the acoustic emission of the blades of the mirror suspension for a gravitational wave interferometer
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