Showing papers by "Enrico Calloni published in 2007"
TL;DR: In this paper, the authors report the status of the Virgo detector and describe the actual detector sensitivity as well as the limiting noises and the mid-term plans for the next few months.
Abstract: The commissioning of the Virgo gravitational wave detector has restarted after several major hardware upgrades carried out during winter 2005. Now Virgo is fully operative and its sensitivity greatly improved and continually improving. A program of short scientific data taking has already started and Virgo is moving towards a period of continuous data taking, which should start at the end of May 2007. The actual status of the Virgo detector is reported, describing the actual detector sensitivity as well as the limiting noises and the mid-term plans.
63 citations
TL;DR: In this paper, the authors derived a set of general relativistic cardinal equations for the equilibrium of an extended body in a uniform gravitational field, which are essential for a proper understanding of the mechanics of suspended relativism systems.
Abstract: This paper derives a set of general relativistic cardinal equations for the equilibrium of an extended body in a uniform gravitational field. These equations are essential for a proper understanding of the mechanics of suspended relativistic systems. As an example, the prototypical case of a suspended vessel filled with radiation is discussed. The mechanics of Casimir apparatuses at rest in the gravitational field of the Earth is then considered. Starting from an expression for the Casimir energy-momentum tensor in a weak gravitational field recently derived by the authors, it is shown here that, in the case of a rigid cavity supported by a stiff mount, the weight of the Casimir energy E c stored in the cavity corresponds to a gravitational mass M = E c /c 2 , in agreement with the covariant conservation law of the regularized energy-momentum tensor. The case of a cavity consisting of two disconnected plates supported by separate mounts, where the two measured forces cannot be obtained by straightforward arguments, is also discussed.
29 citations
TL;DR: In this article, the authors presented the preliminary results of an analysis aimed to search for bursts of gravitational waves associated with the long GRB 050915a, which was detected by the Swift satellite in 2005, when the Virgo detector was engaged in one of its science runs.
Abstract: In the framework of the expected association between gamma-ray bursts and gravitational wave signals, we present the preliminary results of an analysis aimed to search for bursts of gravitational waves associated with the long GRB 050915a. GRB 050915a was detected by the Swift satellite in 2005, when the Virgo detector was engaged in one of its science runs, namely the C7 run, during which the best sensitivity attained in 2005 was exhibited. This offered the opportunity for the first coincident analysis between a gamma-ray burst and the Virgo gravitational wave detector. Here we give an overview of this ongoing analysis, which at the end will play the role of a prototype, crucial in defining a methodology for gamma-ray burst triggered searches with Virgo. The final results of our analysis will also allow us to evaluate up to which level Virgo will be able to constrain the amplitude of the gravitational wave signal from a typical long gamma-ray burst.
28 citations
23 citations
TL;DR: The techniques developed for the measurement of the optical parameters of Virgo are presented and these parameters are compared with the Virgo specifications.
Abstract: The Virgo interferometer, aimed at detecting gravitational waves, is now in a commissioning phase. Measurements of its optical properties are needed for the understanding of the instrument. We present the techniques developed for the measurement of the optical parameters of Virgo. These parameters are compared with the Virgo specifications.
17 citations
TL;DR: In this article, the authors describe the analysis performed in the data of C6 and C7 commissioning runs of Virgo for the search of periodic sources of gravitational waves, covering the frequency range between 50 Hz and 1050 Hz and neutron star spin-down rate below 1.58? 10?8 Hz s?1.
Abstract: In this paper, we describe the analysis performed in the data of C6 and C7 commissioning runs of Virgo for the search of periodic sources of gravitational waves. The analysis is all-sky, covers the frequency range between 50 Hz and 1050 Hz and neutron star spin-down rate below 1.58 ? 10?8 Hz s?1. Coincidences in the source parameter space between candidates found in the two data sets are required to reduce the false alarm probability. The procedure used to estimate the detection efficiency of the analysis pipeline, through the injection of simulated signals in the data, is also described.
14 citations
TL;DR: In this article, preliminary results on the measurement of variations of the Casimir energy in rigid cavities through its influence on the superconducting transition of in-cavity aluminium thin films were reported.
Abstract: We report on preliminary results on the measurement of variations of the Casimir energy in rigid cavities through its influence on the superconducting transition of in-cavity aluminium (Al) thin films. After a description of the experimental apparatus we report on a measurement made with thermal photons, discussing its implications for the zero-point photons case. Finally we show the preliminary results for the zero-point case.
12 citations
TL;DR: In this article, the authors present the progress of the coalescing binary search activities in Virgo, and describe details of the detection pipeline including hardware injections, vetoes, and parameter estimation, using recent data taking.
Abstract: The interferometric gravitational wave detector Virgo is undergoing an advanced phase of its commissioning, during which short runs are routinely performed, in which data are analyzed online and offline, searching for signals from coalescing binary systems. In this report we present the progress of the coalescing binaries search activities in Virgo, and we describe details of the detection pipeline including hardware injections, vetoes, and parameter estimation, using recent data taking.
12 citations
TL;DR: In this article, the authors presented a description of the work of detection and identification of frequency lines in the Virgo dark fringe data from run C7 using pulsar search analysis.
Abstract: The paper presents a description of the work of detection and identification of frequency lines in the Virgo dark fringe data from run C7. A number of methods are highlighted by which noise frequency lines are detected by data analysis and measurements in the laboratory. In this paper we give a description of the list of noise line candidates provided by the pulsar search analysis, the investigation of 10 Hz (and harmonics) noise, violin modes, noise from the end station buildings' air conditioners, sidebands in calibration lines and aliasing in the 4 kHz reconstructed data.
11 citations
TL;DR: In this paper, the authors show that the standard way for signal timing is not an optimal choice and the timing precision can be improved referring to a time when the signal crosses some reference frequency, whose optimal value depends on the detector sensitivity.
Abstract: As they take data and improve their sensitivities, interferometric gravitational wave detectors will eventually detect signals emitted by inspiralling compact binary systems. Determining the sky position of the source will require that the signal be recorded in several detectors. The precision of the source direction determination will be driven by that of the time-of-flight measurements between detectors, and ultimately by the timing precision at the level of each detector. The latter is limited by the noise of the detector and the use of template banks, which introduce some mismatches between the parameters of the signal and the parameters of the template used to detect it. The standard way for signal timing is based on referring to the end time of the signal. In this paper we show that this is not an optimal choice and the timing precision can be improved referring to a time when the signal crosses some reference frequency, whose optimal value depends on the detector sensitivity.
11 citations
TL;DR: In this paper, various techniques developed in order to reach its target extreme performance are outlined, and the 3-km-long Virgo gravitational wave antenna, which will be particularly sensitive in the low-frequency range (10-100 Hz), is presently in its commissioning phase.
TL;DR: In this article, an adaptive optics (AO) system for the control of geometrical fluctuations in a laser beam, based on the interferometric detection of phase front, is presented.
TL;DR: The analysis performed on data acquired during Weekly Science Runs to explore and define the data quality cut and veto studies for burst analysis for gravitational wave bursts is reported on.
Abstract: Virgo started collecting science data during weekends in order to not interfere with commissioning activities. The goal of Weekly Science Runs is to ease the transition between commissioning periods and data taking periods, in addition to providing data sets exploiting the stationary behavior of the detector. The detection of gravitational wave (GW) bursts emitted by core collapse of supernovae is one of the most difficult tasks for the GW community due to the fact that there are uncertainties in the exact shape of the waveforms, as we do not have complete models. A major task for this kind of detection effort is the cleaning of the event triggers found by the detection pipelines, namely the removal of accidental transient signals due to noise source events. In order to clean our data from false GW events, we need to define a strategy for data quality cut and veto of auxiliary and environmental monitoring channels. In this paper we report on the analysis we performed on data acquired during Weekly Science Runs to explore and define the data quality cut and veto studies for burst analysis.
12 Mar 2007
TL;DR: HAL as mentioned in this paper is a multi-disciplinary open access archive for the deposit and dissemination of scientific research documents, whether they are published or not, which may come from teaching and research institutions in France or abroad, or from public or private research centers.
Abstract: HAL is a multi-disciplinary open access archive for the deposit and dissemination of scientific research documents, whether they are published or not. The documents may come from teaching and research institutions in France or abroad, or from public or private research centers. L’archive ouverte pluridisciplinaire HAL, est destinée au dépôt et à la diffusion de documents scientifiques de niveau recherche, publiés ou non, émanant des établissements d’enseignement et de recherche français ou étrangers, des laboratoires publics ou privés. Noise budget and noise hunting in VIRGO F. Acernese, P. Amico, M. Alshourbagy, F. Antonucci, S. Aoudia, P. Astone, S. Avino, D. Babusci, G. Ballardin, F. Barone, et al.
11 Mar 2007
TL;DR: HAL as discussed by the authors is a multi-disciplinary open access archive for the deposit and dissemination of scientific research documents, whether they are published or not, which may come from teaching and research institutions in France or abroad, or from public or private research centers.
Abstract: HAL is a multi-disciplinary open access archive for the deposit and dissemination of scientific research documents, whether they are published or not. The documents may come from teaching and research institutions in France or abroad, or from public or private research centers. L’archive ouverte pluridisciplinaire HAL, est destinée au dépôt et à la diffusion de documents scientifiques de niveau recherche, publiés ou non, émanant des établissements d’enseignement et de recherche français ou étrangers, des laboratoires publics ou privés. The Automatic Alignment System of the Virgo Interferometer F. Acernese, P. Amico, M. Alshourbagy, F. Antonucci, S. Aoudia, P. Astone, S. Avino, D. Babusci, G. Ballardin, F. Barone, et al.
12 Nov 2007
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.
17 Aug 2007
TL;DR: The VIRGO detector as discussed by the authors is in the final commissioning phase and some preliminary data has already been acquired, and the aim is to directly detect gravitational waves emitted by compact objects at the time of coalescence and by other astrophysical sources.
Abstract: The gravitational wave detector VIRGO is in the final commissioning phase and some preliminary data has already been acquired The aim of VIRGO is to directly detect gravitational waves emitted by compact objects at the time of coalescence and by other astrophysical sources Here we report on the present sensitivity for detecting these sources and what we will achieve in the near future We also discuss some details of our data analysis methods and we show some preliminary results related to the fraction of the Universe that we can observe
01 Mar 2007-Nuclear Instruments & Methods in Physics Research Section A-accelerators Spectrometers Detectors and Associated Equipment
TL;DR: Aladin2 as discussed by the authors is an experiment devoted to the first measurement of variations of Casimir energy in a rigid body, and the main short term scientific motivation relies on the possibility of the first demonstration of a phase transition influenced by vacuum fluctuations while, in the long-term and in the mainframe of the cosmological constant problem, it can be regarded as the first step towards a measurement of the weight of vacuum energy.
Abstract: Aladin2 is an experiment devoted to the first measurement of variations of Casimir energy in a rigid body. The main short term scientific motivation relies on the possibility of the first demonstration of a phase transition influenced by vacuum fluctuations while, in the long-term and in the mainframe of the cosmological constant problem, it can be regarded as the first step towards a measurement of the weight of vacuum energy. In this paper, after a presentation of the guiding principle of the measurement, the experimental apparatus and sensitivity studies on final cavities will be presented.
12 Nov 2007
TL;DR: In this article, the status of the real-time distributed control system of the Virgo interferometric detector of Gravitational waves, its performances and planned improvements are described, and a specially designed hierarchical architecture for the local control system, necessary for managing the hard task of filtering all the environments noises that limit the sensitivity of the interferometer.
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 working 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, necessary for managing the hard task of filtering all the environments noises that limit the sensitivity of the interferometer, supervised by a distributed global control system to maintain the detector fully operational. In this paper we described the status of the real - time distributed control system of the Virgo interferometric detector of Gravitational waves, its performances and planned improvements.
01 Mar 2007-Nuclear Instruments & Methods in Physics Research Section A-accelerators Spectrometers Detectors and Associated Equipment
TL;DR: In this paper, the experimental results of the application of Adaptive Optics (AO) technique to control the laser beam in a gravitational wave interferometer were presented, focusing on two specific applications: reduction of laser geometrical aberrations by using an AO system based on interferometric wavefront detection and the use of deformable mirrors for the generation of the non-Gaussian flat laser beams proposed for the reduction of thermoelastic noise.
Abstract: In this paper we present the experimental results of the application of Adaptive Optics (AO) technique to control the laser beam in gravitational wave interferometer. In particular, we focus our attention on two specific applications. The first one is the reduction of laser geometrical aberrations by using an AO system based on interferometric wavefront detection. The second application is the use of deformable mirrors for the generation of the non-Gaussian flat laser beams proposed for the reduction of thermoelastic noise in future detectors.
01 Jan 2007
TL;DR: HAL as discussed by the authors is a multi-disciplinary open access archive for the deposit and dissemination of scientific research documents, whether they are published or not, which may come from teaching and research institutions in France or abroad, or from public or private research centers.
Abstract: HAL is a multi-disciplinary open access archive for the deposit and dissemination of scientific research documents, whether they are published or not. The documents may come from teaching and research institutions in France or abroad, or from public or private research centers. L’archive ouverte pluridisciplinaire HAL, est destinée au dépôt et à la diffusion de documents scientifiques de niveau recherche, publiés ou non, émanant des établissements d’enseignement et de recherche français ou étrangers, des laboratoires publics ou privés. Future Virgo Upgrades F. Acernese, P. Amico, M. Alshourbagy, F. Antonucci, S. Aoudia, P. Astone, S. Avino, D. Babusci, G. Ballardin, F. Barone, et al.