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

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.Comment: 15 pages, 7 figures: data for plots and archived public version at https://dcc.ligo.org/cgi-bin/DocDB/ShowDocument?docid=70814&version=19, see also the public announcement at http://www.ligo.org/science/Publication-S6BurstAllSky

Einstein gravitational wave Telescope conceptual design study

This document describes the Conceptual Design of a third generation gravitational wave observatory named Einstein Telescope (“ET”). The design of this new research infrastructure has been realised with the support of the European Community’s Seventh Framework Programme (FP7/2007-2013) under grant agreement n 211743. In this document are described the fundamental design options, the site requirements, the main technological solutions, a rough evaluation of the costs and a schematic time plan

The seismic Superattenuators of the Virgo gravitational waves interferometer

The Virgo experiment, located near Pisa, Italy, is a large laser Michelson interferometer aiming at the first direct detection of gravitational waves. The interferometer monitors the relative distance of its mirrors placed at the ends of two 3 km-long perpendicular arms. The goal is to measure spectral differential variations of the arm lengths of 10(-18) m/Hz(1/2) in the frequency range from 10 Hz to 10 kHz. Avoiding spurious motions of the optical components is therefore essential to detect gravitational waves. Since the ground motion is 9 orders of magnitude larger than the arm length variations induced by gravitational waves, the seismic noise is the dominant low frequency noise source for terrestrial gravitational wave interferometers. The seismic isolation is obtained suspending the mirrors by an 8-meter tall chain of cascaded mechanical filters, called "Superattenuator" (SA). The Superattenuator is a passive device acting as a low pass filter in all six degrees of freedom, capable of attenuating the ground motion by more than 10 orders of magnitude, starting from a few Hz. To further reduce the seismic disturbances, the filter chain is suspended from an actively stabilized platform that compensates for low frequency and large amplitude oscillations caused by the mechanical resonances of the chain. In this article we describe the Superattenuator together with its control system, and we report about its performance

Performances of the Virgo interferometer longitudinal control system

The performances of the longitudinal sensing and control system of the Virgo gravitational wave detector are described. This system is able to stably maintain the RMS residual fluctuation of the interferometer longitudinal degrees of freedom around or below 10-11m, compatible with the original Virgo requirements. Moreover the detector sensitivity is not limited by longitudinal control noise at any frequency. Indeed the noise re-introduced by the longitudinal control system does not affect the Virgo design sensitivity

In-vacuum Faraday isolation remote tuning

none170sìIn-vacuum Faraday isolators (FIs) are used in gravitational wave interferometers to prevent the disturbance caused by light reflected back to the input port from the interferometer itself. The efficiency of the optical isolation is becoming more critical with the increase of laser input power. An in-vacuum FI, used in a gravitational wave experiment (Virgo), has a 20 mm clear aperture and is illuminated by an almost 20 W incoming beam, having a diameter of about 5 mm. When going in vacuum at 10−6 mbar, a degradation of the isolation exceeding 10 dB was observed. A remotely controlled system using a motorized λ=2 waveplate inserted between the first polarizer and the Faraday rotator has proven its capability to restore the optical isolation to a value close to the one set up in air.mixed Accadia T; Acernese F; Antonucci F; Aoudia S; Arun KG; Astone P; Ballardin G; Barone F; Barsuglia M; Bauer TS; Beker MG; Bigotta S; Birindelli S; Bitossi M; Bizouard MA; Blom M; Boccara C; Bondu F; Bonelli L; Bosi L; Braccini S; Bradaschia C; Brillet A; Brisson; Budzynski R; Bulik T; Bulten HJ; Buskulic D; Cagnoli G; Calloni E; Campagna E; Canuel B; Carbognani F; Cavalier F; Cavalieri R; Cella G; Cesarini E; Chassande-Mottin E; Chincarini A; Cleva F; Coccia E; Colacino CN; Colas J; Colla A; Colombini M; Corda C; Corsi A; Coulon JP; Cuoco E; D'Antonio S; Dari A; Dattilo V; Davier M; Day R; De Rosa R; del Prete M; Di Fiore L; Di Lieto A; Emilio MD; Di Virgilio A; Dietz A; Drago M; Fafone V; Ferrante I; Fidecaro F; Fiori I; Flaminio R; Fournier JD; Franc J; Frasca S; Frasconi F; Freise A; Gammaitoni L; Garufi F; Gemme G; Genin E; Gennai A; Giazotto A; Gouaty R; Granata M; Greverie C; Guidi GM; Heitmann H; Hello P; Hild S; Huet D; Jaranowski P; Kowalska I; Królak A; La Penna P; Leroy N; Letendre N; Li TG; Lorenzini M; Loriette V; Losurdo G; Mackowski JM; Majorana E; Man N; Mantovani M; Marchesoni F; Marion F; Marque J; Martelli F; Masserot A; Michel C; Milano L; Minenkov Y; Mohan M; Moreau J; Morgado N; Morgia A; Mosca S; Moscatelli V; Mours B; Neri I; Nocera F; Pagliaroli G; Palladino L; Palomba C; Paoletti F; Pardi S; Parisi M; Pasqualetti A; Passaquieti R; Passuello D; Persichetti G; Pichot M; Piergiovanni F; Pietka M; Pinard L; Poggiani R; Prato M; Prodi GA; Punturo M; Puppo P; Rabaste O; Rabeling DS; Rapagnani P; Re V; Regimbau T; Ricci F; Robinet F; Rocchi A; Rolland L; Romano R; Rosińska D; Ruggi P; Sassolas B; Sentenac D; Sturani R; Swinkels B; Toncelli A; Tonelli M; Tournefier E; Travasso F; Trummer J; Vajente G; van den Brand JF; van der Putten S; Vavoulidis M; Vedovato G; Verkindt D; Vetrano F; Viceré A; Vinet JY; Vocca H; Was M; Yvert M; Virgo C accadia, T;  acernese, F;  antonucci, F;  aoudia, S;  arun, Kg;  astone, P;  ballardin, G;  barone, F;  barsuglia, M;  bauer, Ts;  beker, Mg;  bigotta, S;  birindelli, S;  bitossi, M;  bizouard, Ma;  blom, M;  boccara, C;  bondu, F;  bonelli, L;  bosi, L;  braccini, S;  bradaschia, C;  brillet, A;  brisson, ;  budzynski, R;  bulik, T;  bulten, Hj;  buskulic, D;  cagnoli, G;  calloni, E;  campagna, E;  canuel, B;  carbognani, F;  cavalier, F;  cavalieri, R;  cella, G; Cesarini, Elisabetta;  Chassande Mottin, E;  chincarini, A;  cleva, F;  coccia, E;  colacino, Cn;  colas, J;  colla, A;  colombini, M;  corda, C;  corsi, A;  coulon, Jp;  cuoco, E;  d'Antonio, S;  dari, A;  dattilo, V;  davier, M;  day, R;  De Rosa, R;  del Prete, M;  Di Fiore, L;  Di Lieto, A;  emilio, Md;  Di Virgilio, A;  dietz, A;  drago, M;  fafone, V;  ferrante, I;  fidecaro, F;  fiori, I;  flaminio, R;  fournier, Jd;  franc, J;  frasca, S;  frasconi, F;  freise, A;  gammaitoni, L;  garufi, F;  gemme, G;  genin, E;  gennai, A;  giazotto, A;  gouaty, R;  granata, M;  greverie, C; Guidi, GIANLUCA MARIA;  heitmann, H;  hello, P;  hild, S;  huet, D;  jaranowski, P;  kowalska, I;  królak, A;  La Penna, P;  leroy, N;  letendre, N;  li, Tg;  lorenzini, M;  loriette, V;  losurdo, G;  mackowski, Jm;  majorana, E;  man, N;  mantovani, M;  marchesoni, F;  marion, F;  marque, J; Martelli, Filippo;  masserot, A;  michel, C;  milano, L;  minenkov, Y;  mohan, M;  moreau, J;  morgado, N;  morgia, A;  mosca, S;  moscatelli, V;  mours, B;  neri, I;  nocera, F;  pagliaroli, G;  palladino, L;  palomba, C;  paoletti, F;  pardi, S;  parisi, M;  pasqualetti, A;  passaquieti, R;  passuello, D;  persichetti, G;  pichot, M; Piergiovanni, Francesco;  pietka, M;  pinard, L;  poggiani, R;  prato, M;  prodi, Ga;  punturo, M;  puppo, P;  rabaste, O;  rabeling, Ds;  rapagnani, P;  re, V;  regimbau, T;  ricci, F;  robinet, F;  rocchi, A;  rolland, L;  romano, R;  rosińska, D;  ruggi, P;  sassolas, B;  sentenac, D; Sturani, Riccardo;  swinkels, B;  toncelli, A;  tonelli, M;  tournefier, E;  travasso, F;  trummer, J;  vajente, G;  van den Brand, Jf;  van der Putten, S;  vavoulidis, M;  vedovato, G;  verkindt, D; Vetrano, Flavio; Vicere', Andrea;  vinet, Jy;  vocca, H;  was, M;  yvert, M; Virgo, C

Status of the Commissioning of the Virgo Interferometer

Long baseline optical interferometry is a promising technique for the detection of gravitational waves [1], [2], [3], [4]. The French-Italian detector Virgo is a Michelson interferometer with 3 km arms, equipped with high storage time Fabry-Perot cavities. In this kind of detectors, the passage of gravitational waves would be sensed as a differential length variation of the arms. After the end of the second Virgo Science Run, lasting from July 2009 to the beginning of January 2010, some important upgrades have been carried out; in particular, the mirrors of the Fabry-Perot cavities, which act as test masses of the detector, have been replaced by new ones with an higher reflectivity, which should increase by three times the finesse of the cavities; moreover the mirrors are now suspended by silica fibers in a monolithic assembly expected to significantly lower the thermal noise. Finally, the digital signal processing electronics and the global control system have been largely improved. We will present the status of the commissioning of the Virgo interferometer

In-vacuum Faraday isolation remote tuning

In-vacuum Faraday isolators (FIs) are used in gravitational wave interferometers to prevent the disturbance caused by light reflected back to the input port from the interferometer itself. The efficiency of the optical isolation is becoming more critical with the increase of laser input power. An in-vacuum FI, used in a gravitational wave experiment (Virgo), has a 20 mm clear aperture and is illuminated by an almost 20 W incoming beam, having a diameter of about 5 mm. When going in vacuum at 10(-6) mbar, a degradation of the isolation exceeding 10 dB was observed. A remotely controlled system using a motorized lambda/2 waveplate inserted between the first polarizer and the Faraday rotator has proven its capability to restore the optical isolation to a value close to the one set up in air. c 2010 Optical Society of Americ