Showing papers by "F. Fidecaro published in 2008"
TL;DR: In this paper, the optical scheme of the interferometer and various optical techniques used in the experiment, such as the laser source, control, alignment, stabilization and detection strategies are outlined.
Abstract: Virgo, designed, constructed and developed by the French-Italian VIRGO collaboration located in Cascina (Pisa, Italy) and aiming to detect gravitational waves, is a ground-based power recycled Michelson interferometer, with 3 km long suspended Fabry-Perot cavities. The first Virgo scientific data-taking started in mid-May 2007, in coincidence with the corresponding LIGO detectors. The optical scheme of the interferometer and the various optical techniques used in the experiment, such as the laser source, control, alignment, stabilization and detection strategies are outlined. The future upgrades that are planned for Virgo from the optical point of view, especially concerning the evolution of the Virgo laser, are presented. Finally, the next generation of the gravitational wave detector (advanced Virgo) is introduced from the point of view of the laser system.
46 citations
TL;DR: In this paper, an analysis aimed to search for a burst of gravitational waves in coincidence with gamma-ray burst 050915a was presented, where the best upper limit strain amplitudes were obtained are Hz−1/2 around ~200-1500 Hz.
Abstract: In the framework of the expected association between gamma-ray bursts and gravitational waves, we present results of an analysis aimed to search for a burst of gravitational waves in coincidence with gamma-ray burst 050915a. This was a long duration gamma-ray burst detected by Swift during September 2005, when the Virgo gravitational wave detector was engaged in a commissioning run during which the best sensitivity attained in 2005 was exhibited. This offered the opportunity for Virgo's first search for a gravitational wave signal in coincidence with a gamma-ray burst. The result of our study is a set of strain amplitude upper limits, based on the loudest event approach, for different but quite general types of burst signal waveforms. The best upper limit strain amplitudes we obtain are Hz−1/2 around ~200–1500 Hz. These upper limits allow us to evaluate the level up to which Virgo, when reaching nominal sensitivity, will be able to constrain the gravitational wave output associated with a long burst. Moreover, the analysis presented here plays the role of a prototype, crucial in defining a methodology for gamma-ray burst triggered searches with Virgo and opening the way for future joint analyses with LIGO.
40 citations
TL;DR: A broad review of LIGO's astrophysically triggered searches and the sources they target can be found in this article, where the expected frequency range, source energetics, directional and progenitor information are also available.
Abstract: In gravitational-wave detection, special emphasis is put onto searches that focus on cosmic events detected by other types of astrophysical observatories. The astrophysical triggers, e.g. from γ-ray and x-ray satellites, optical telescopes and neutrino observatories, provide a trigger time for analyzing gravitational-wave data coincident with the event. In certain cases the expected frequency range, source energetics, directional and progenitor information are also available. Beyond allowing the recognition of gravitational waveforms with amplitudes closer to the noise floor of the detector, these triggered searches should also lead to rich science results even before the onset of Advanced LIGO. In this paper we provide a broad review of LIGO's astrophysically triggered searches and the sources they target.
37 citations
TL;DR: A methodology of network data analysis applied to the search for coincident burst excitations over a 24 h long data set collected by AURIGA, EXPLORER, NAUTILUS and Virgo detectors, aiming at setting confidence intervals as stringent as possible in terms of the rate of the selected source models.
Abstract: We present a methodology of network data analysis applied to the search for coincident burst excitations over a 24 h long data set collected by AURIGA, EXPLORER, NAUTILUS and Virgo detectors during September 2005. The search of candidate triggers was performed independently on each of the data sets from single detectors. We looked for two-fold time coincidences between these candidates using an algorithm optimized for a given population of sources and we calculated the efficiency of detection through injections of templated signal waveforms into the streams of data. To this end we have considered the case of signals shaped as damped sinusoids coming from the galactic center direction. Our method targets an optimal balance between high efficiency and low false alarm rate, aiming at setting confidence intervals as stringent as possible in terms of the rate of the selected source models.
22 citations
University of Salerno1, University of Pisa2, University of Perugia3, Artemis4, Centre national de la recherche scientifique5, Laboratoire d'Annecy-le-Vieux de physique des particules6, Massachusetts Institute of Technology7, Paris Diderot University8, University of Urbino9, University of Florence10, University of Rome Tor Vergata11, University of Siena12, Sapienza University of Rome13, VU University Amsterdam14
TL;DR: In this paper, the authors describe the variable finesse lock acquisition technique and discuss the performance of the whole locking system and discuss its performance in the Virgo interferometer for gravitational wave detection.
19 citations
University of Salerno1, University of Pisa2, University of Perugia3, Artemis4, Laboratoire d'Annecy-le-Vieux de physique des particules5, Centre national de la recherche scientifique6, VU University Amsterdam7, University of Urbino8, University of Florence9, University of Rome Tor Vergata10, University of Siena11, Sapienza University of Rome12, University of L'Aquila13, Scuola Normale Superiore di Pisa14
TL;DR: The VIRGO interferometer is the largest ground-based European gravitational wave detector operating at the EGO Laboratory in the Pisa, Italy; countryside as discussed by the authors, where relevant progress have been done in approaching its design sensitivity all over the detection bandwidth.
Abstract: The VIRGO interferometer is the largest ground based European gravitational wave detector operating at the EGO Laboratory in the Pisa, Italy; countryside. During the last commissioning period relevant progress have been done in approaching its design sensitivity all over the detection bandwidth. Thanks to the effort of the whole Collaboration a long scientific run has been done collecting data for more than 4 months in conjunction with the LIGO detectors. The results obtained from the detector point of view are: a very good stability and a duty-cycle as high as 81% in science mode. In this paper we present the status of the VIRGO interferometer giving an overview of the experimental apparatus together with its most relevant features.
18 citations
TL;DR: A model evaluating changes in the optical isolation of a Faraday isolator when passing from air to vacuum in terms of different thermal effects in the crystal reproduces with a great accuracy the experimental data measured on Virgo and on a test bench.
Abstract: We describe a model evaluating changes in the optical isolation of a Faraday isolator when passing from air to vacuum in terms of different thermal effects in the crystal. The changes are particularly significant in the crystal thermal lensing (refraction index and thermal expansion) and in its Verdet constant and can be ascribed to the less efficient convection cooling of the magneto-optic crystal of the Faraday isolator. An isolation decrease by a factor of 10 is experimentally observed in a Faraday isolator that is used in a gravitational wave experiment (Virgo) with a 10 W input laser when going from air to vacuum. A finite element model simulation reproduces with a great accuracy the experimental data measured on Virgo and on a test bench. A first set of measurements of the thermal lensing has been used to characterize the losses of the crystal, which depend on the sample. The isolation factor measured on Virgo confirms the simulation model and the absorption losses of 0.0016 ± 0.0002/cm for the TGG magneto-optic crystal used in the Faraday isolator.
16 citations
University of Salerno1, University of Pisa2, University of Perugia3, Artemis4, Centre national de la recherche scientifique5, Laboratoire d'Annecy-le-Vieux de physique des particules6, University of Urbino7, University of Florence8, University of Rome Tor Vergata9, University of Siena10, Sapienza University of Rome11, VU University Amsterdam12
TL;DR: The first Virgo long science run (VSR1) lasted 136 days from 18th May 2007 to 28th June 2007 as discussed by the authors, and several noise sources were identified and reduced during the run.
Abstract: The first Virgo long science run (VSR1) lasted 136 days, from 18th May 2007. During the run several noise sources were identified and reduced; this significantly improved the detector sensitivity between the start and the end of the run. We describe three noise studies, showing how data monitoring programs and simple analysis tools permitted the first detection of the noise and provided useful information regarding its origin.
13 citations
22 Feb 2008
TL;DR: The status of the real-time distributed control system of the Virgo interferometric detector of Gravitational waves, its performances and planned improvements are described.
Abstract: The VIRGO experiment for the detection of gravitational waves is a big challenge both for physics and for technology. In particular, to satisfy the stringent requirements on the alignment and position of its suspended optical components to keep the detector at its point, a very complex distributed and supervised control system has been implemented. The current constraints are about 10-10 m RMS for the longitudinal control ("Locking") and 10-9 rad RMS for the angular degrees of freedom ("Alignment"). These requirements are satisfied by means of a specially designed hierarchical architecture for the local control system. It is necessary for managing the hard task of filtering all the environmental noises that limit the sensitivity of the interferometer. On the other end, the interferometer is supervised by a distributed global control system to maintain the detector fully operational. In this paper we describe the status of the real-time distributed control system of the Virgo interferometric detector of Gravitational waves, its performances and planned improvements.
8 citations
Patent•
Eni1
TL;DR: An apparatus and a method for measuring the gravitational acceleration on the ground, comprising a base frame (31), a resonator (10) having a first disc of sapphire integral to said base frame, arranged at a minimum distance from said first mass (2) and aligned vertically with respect to the second mass (3) such that said first and said second disc (1 and 2) formed a resonance for electromagnetic signals as discussed by the authors.
Abstract: An apparatus and a method for measuring the gravitational acceleration on the ground, comprising a base frame (31), a resonator (10) having a first disc of sapphire (2) integral to said base frame (31), an a second disc of sapphire (1) arranged at a minimum distance from said first mass (2) and aligned vertically with respect to said first mass (2) such that said first and said second disc (1 and 2) form a resonator for electromagnetic signals (10); a cantilever arm (41) connected to said base frame (31) and holding resiliently the second disc (1); a magnetic probe (11) for applying an electromagnetic signal to said resonator (10) arranged according to a plane existing between the two discs (1 and 2); a linear electric probe (12), arranged under the fixed disc (2) aligned vertically with respect to its side edge, for measuring a resonance frequency of said resonator responsive to said electromagnetic signal, means for correlating the variation of said resonance frequency to a variation of distance between said discs (1 and 2), and means for correlating the variation of distance to local gravitational acceleration
8 citations
TL;DR: The main hardware and software components developed for the data acquisition system (DAQ) and its current architecture are overviewed, and its connections with interferometer's controls are discussed, especially through the automation of the interferometers' startup procedure.
Abstract: Virgo is an experiment aiming at the detection of gravitational waves emitted by astrophysical sources. Its detector, based on a 3 km arms interferometer, is a complex setup which requires several digital control loops running up to 10 kHz, an accurate and reliable central timing system and an efficient data acquisition, all of them being distributed over 3 km. We overview here the main hardware and software components developed for the data acquisition system (DAQ) and its current architecture. Then, we briefly discuss its connections with interferometer's controls, especially through the automation of the interferometer's startup procedure. Then, we describe the tools used to monitor the DAQ and the performances we measured with them. Finally, are described also the tools developed for the online detector monitoring, mandatory complement of the DAQ for the commissioning of the Virgo detector.
01 Sep 2008
TL;DR: In this article, the authors present a survey of the state-of-the-art work in the field of cyber-physical medicine and propose a set of guidelines for the use of virtual reality in medical applications.
Abstract: F. Acernese6, P. Amico10, M. Alshourbagy11, F. Antonucci 12, S. Aoudia7, P. Astone12, S. Avino6, D. Babusci4, G. Ballardin2, F. Barone6, L. Barsotti11, M. Barsuglia8 , F. Beauville1, S. Bigotta11, S. Birindelli11, M.A. Bizouard8, C. Boccara9, F. Bondu7, L. Bosi10, C. Bradaschia11, S. Braccini11,A. Brillet7, V. Brisson8, L. Brocco12, D. Buskulic1, E. Calloni6, E. Campagna3, F. Carbognani2, F. Cavalier8, R. Cavalieri2, G. Cella11, E. Cesarini3, E. Chassande-Mottin7, N. Christensen2, C. Corda11, A. Corsi12, F. Cottone10, A.-C. Clapson8, F. Cleva7, J.-P. Coulon7, E. Cuoco2, A. Dari10, V. Dattilo2, M. Davier8, M. del Prete2, R. De Rosa6, L. Di Fiore6, A. Di Virgilio11, B. Dujardin7, A. Eleuteri6, I. Ferrante11, F. Fidecaro11, I. Fiori11, R. Flaminio1, 2, J.-D. Fournier7, O.Francois2, S. Frasca12, F. Frasconi2, 11, L. Gammaitoni10, F. Garufi6, E. Genin2, A. Gennai11, A. Giazotto11, G. Giordano4, L. Giordano6, R. Gouaty1, D. Grosjean1, G. Guidi3, S. Hebri2, H. Heitmann7, P. Hello8, S. Karkar1, S. Kreckelbergh8, P. La Penna2, M. Laval7, N. Leroy8, N. Letendre1, B. Lopez2, Lorenzini3, V. Loriette9, G. Losurdo3, J.-M. Mackowski5, E. Majorana12, C. N. Man7, M. Mantovani11, F. Marchesoni10, F. Marion1, J. Marque2, F. Martelli3, A. Masserot1, M. Mazzoni3, L. Milano6, F. Menzinger2, C. Moins2, J. Moreau9, N. Morgado5, B. Mours1, F. Nocera2, A. Pai12, C. Palomba12, F. Paoletti2, 11, S. Pardi6, A. Pasqualetti2, R. Passaquieti11, D. Passuello11, B. Perniola3, F. Piergiovanni3, L. Pinard5, R. Poggiani11, M. Punturo10, P. Puppo12, K. Qipiani6, P. Rapagnani12, V. Reita9, A. Remillieux5, F. Ricci12, I. Ricciardi6, P. Ruggi 2, G. Russo6, S. Solimeno6, A. Spallicci7, R. Stanga3, T. Marco11, M. Tonelli11, A. Toncelli11, E. Tournefier1, F. Travasso10, C. Tremola11, G. Vajente 11, D. Verkindt1, F. Vetrano3, A. Vicere3, J.-Y. Vinet7, H. Vocca10 and M. Yvert1 1Laboratoire d’Annecy-le-Vieux de Physique des Particules (LAPP), IN2P3/CNRS, Universite de Savoie, Annecy-le-Vieux, France;
01 Jan 2008
TL;DR: The main hardware and software components developed for the data acquisition system (DAQ) and its current architecture are overviewed and the tools used to monitor the DAQ and the performances the authors measured with them are described.
Abstract: Virgo is an experiment aiming at the detection of grav- itational waves emitted by astrophysical sources. Its detector, based on a 3 km arms interferometer, is a complex setup which requires several digital control loops running up to 10 kHz, an accurate and reliable central timing system and an efficient data acquisi- tion, all of them being distributed over 3 km. We overview here the main hardware and software components developed for the data acquisition system (DAQ) and its current architecture. Then, we briefly discuss its connections with interferometer's controls, espe- cially through the automation of the interferometer's startup pro- cedure. Then, we describe the tools used to monitor the DAQ and the performances we measured with them. Finally, are described also the tools developed for the online detector monitoring, manda- tory complement of the DAQ for the commissioning of the Virgo detector.
TL;DR: In this article, the authors present a method to search for transient GWs using a network of detectors with different spectral and directional sensitivities: the interferometer Virgo and the bar detector AURIGA.
Abstract: We present a method to search for transient GWs using a network of detectors with different spectral and directional sensitivities: the interferometer Virgo and the bar detector AURIGA. The data analysis method is based on the measurements of the correlated energy in the network by means of a weighted cross-correlation. To limit the computational load, this coherent analysis step is performed around time-frequency coincident triggers selected by an excess power event trigger generator tuned at low thresholds. The final selection of GW candidates is performed by a combined cut on the correlated energy and on the significance as measured by the event trigger generator. The method has been tested on one day of data of AURIGA and Virgo during September 2005. The outcomes are compared to the results of a stand-alone time-frequency coincidence search. We discuss the advantages and the limits of this approach, in view of a possible future joint search between AURIGA and one interferometric detector.