D. Passuello

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The French-Italian interferometric gravitational wave detector VIRGO is currently being commissioned. Its principal instrument is a Michelson interferometer with 3 km long optical cavities in the arms and a powerrecycling mirror. This paper gives an overview of the present status of the system. We report on the presently attained sensitivity and the(More)
  • J Abadie, B P Abbott, +497 authors L Pinard
  • Physical review letters
  • 2011
The gravitational-wave (GW) sky may include nearby pointlike sources as well as stochastic backgrounds. We perform two directional searches for persistent GWs using data from the LIGO S5 science run: one optimized for pointlike sources and one for arbitrary extended sources. Finding no evidence to support the detection of GWs, we present 90% confidence(More)
A stochastic background of gravitational waves is expected to arise from a superposition of a large number of unresolved gravitational-wave sources of astrophysical and cosmological origin. It should carry unique signatures from the earliest epochs in the evolution of the Universe, inaccessible to standard astrophysical observations. Direct measurements of(More)
The gravitational wave detector Virgo is presently being commissioned. A significant part of last year was spent in setting up the cavity length control system. This work was carried out with steps of increasing complexity: locking a simple FabryPerot cavity, then a Michelson interferometer with Fabry-Perot cavities in both arms, and finally recycling the(More)
interferometric gravitational wave detectors must be isolated from seismic noise. The VIRGO vibration isolator, called superattenuator, is fully effective at frequencies above 4 Hz. Nevertheless, the residual motion of the mirror at the mechanical resonant frequencies of the system are too large for the interferometer locking system and must be damped. A(More)
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(More)
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(More)
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(More)
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(More)
We describe APE-100, a SIMD, modular parallel processor architecture for large scale scienti c computations. The largest con guration that will be implemented in the present design will deliver a peak speed of 100 G ops. This performance is, for instance, required for high precision computations in Quantum Chromo Dynamics, for which APE-100 is very well(More)