Abstract We report on the status of the Virgo detector, under commissioning. We will focus on the... more Abstract We report on the status of the Virgo detector, under commissioning. We will focus on the last year's activity. The two commissioning runs performed during 2005 allowed us to reach a sensitivity of h∼ 6× 10− 22. The data obtained during the runs were used to test a few data analysis algorithms, namely coalescing binaries and burst searches. The main improvements made on the detector during this year will be described, as well as the plans and activities foreseen in the coming years.
... 5506: physics of the extended narrow line region* Roberto Maiolino1, Ruggero Stanga1, Marco S... more ... 5506: physics of the extended narrow line region* Roberto Maiolino1, Ruggero Stanga1, Marco Salvati2, and José M. Rodriguez Espinosa3 1 ... Send offprint requests to: R. Maiolino * Based on observations made with the William Herschel Telescope, operated on the island of La ...
We report J, H, and K photometry of 86 stars in 40 elds in the northern hemisphere. The elds are ... more We report J, H, and K photometry of 86 stars in 40 elds in the northern hemisphere. The elds are smaller than or comparable to a 4 4 arcmin eld-of-view, and are roughly uniformly distributed over the sky, making them suitable for a homogeneous broadband calibration network for near-infrared panoramic detectors. K magnitudes range from 8.5 to 14, and J ?K colors from -0.1 to 1.2. The photometry is derived from a total of 3899 reduced images; each star has been measured, on average, 26.0 times per lter on 5.5 nights. Typical errors on the photometry are 0: m 012. Subject headings: methods: data analysis | techniques: photometric { 3 { { 4 {
One of the goal of the gravitational data wave analysts is the knowledge and the accurate estimat... more One of the goal of the gravitational data wave analysts is the knowledge and the accurate estimation of the noise power spectral density of the data taken by the detector, being it necessary in the detection algorithms. In this paper we showed how it is possible estimate the noise power spectral density of gravitational waves detectors using modern parametric techniques and how it is possible whiten the noise data before pass it to the algorithms for the gravitational waves detection. We report the analysis we made on data taken by Caltech 40-meter prototype interferometer to identify its noise power spectral density and to whiten the sequence of noise. We concentrate our study on data taken in November 1994, in particular we analyzed two frames of data: the 18nov94.2.frame and the 19nov94.2.frame. We show that it is possible to whiten these data, to a good degree of whiteness, using a high order whitening filter. Moreover we can choose to whiten only restricted band of frequencies around the region we are interested in, obtaining a higher level of whiteness. 04.80.Nn, 07.05Kf, 07.60Ly, 05.40Ca, 05.40C
The gravitational wave detector VIRGO aims at extending the detection band down to a few Hertz by... more The gravitational wave detector VIRGO aims at extending the detection band down to a few Hertz by isolating the mirrors of the interferometer from seismic noise. This result is achieved by hanging each mirror through an elastic suspension (Superattenuator), designed to filter mechanical vibrations in all the degrees of freedom. An experimental upper limit of the mirror residual seismic noise at a few Hertz is provided in this paper. This is lower than the thermal noise floor, expected to limit the antenna sensitivity in the low frequency range.
The knowledge of the noise power spectral density of an interferometric detector of gravitational... more The knowledge of the noise power spectral density of an interferometric detector of gravitational waves is fundamental for detection algorithms and for the analysis of the data. In this paper we address both the problem of identifying the noise power spectral density of interferometric detectors by parametric techniques and the problem of the whitening procedure of the sequence of data. We will concentrate the study on a power spectral density like that of the Italian-French detector VIRGO and we show that with a reasonable number of parameters we succeed in modelling a spectrum like the theoretical one of VIRGO, reproducing all of its features.
Nuclear Instruments & Methods in Physics Research Section A-accelerators Spectrometers Detectors and Associated Equipment, 2002
Low-power, ultra-high-vacuum compatible, non-contacting position sensors with nanometer resolutio... more Low-power, ultra-high-vacuum compatible, non-contacting position sensors with nanometer resolution and centimeter dynamic range have been developed, built and tested. They have been designed at Virgo as the sensors for low-frequency modal damping of Seismic Attenuation System chains in Gravitational Wave interferometers and sub-micron absolute mirror positioning. One type of these linear variable differential transformers (LVDTs) has been designed to be also insensitive to transversal displacement thus allowing 3D movement of the sensor head while still precisely reading its position along the sensitivity axis. A second LVDT geometry has been designed to measure the displacement of the vertical seismic attenuation filters from their nominal position. Unlike the commercial LVDTs, mostly based on magnetic cores, the LVDTs described here exert no force on the measured structure. r 2002 Elsevier Science B.V. All rights reserved. PACS: 04.80.Nn; 95.30.Sf; 95.55.Ym (H. Tariq). 0168-9002/02/$ -see front matter r 2002 Elsevier Science B.V. All rights reserved. PII: S 0 1 6 8 -9 0 0 2 ( 0 2 ) 0 0 8 0 2 -1
After a sequence of intermediate stages, the interferometer is now being used in the so-called re... more After a sequence of intermediate stages, the interferometer is now being used in the so-called recombined configuration. The input laser beam is spatially filtered by a 144 m long input mode-cleaner before being injected to the main interferometer. The main optics are suspended from so-called \sa s, which provide an excellent seismic isolation. The two 3 km long Fabry-Perot arm cavities are kept in resonance with the laser light, and the Michelson interferometer is held on the dark fringe. An automatic mirror alignment system based on the Anderson technique has been implemented for the arm cavities. The light leaving the dark port contains the gravitational wave signal; this light is filtered by an output mode-cleaner before being detected by a photo detector. This setup is the last step on the way to the final configuration, which will include power recycling.
Abstract We report on the status of the Virgo detector, under commissioning. We will focus on the... more Abstract We report on the status of the Virgo detector, under commissioning. We will focus on the last year's activity. The two commissioning runs performed during 2005 allowed us to reach a sensitivity of h∼ 6× 10− 22. The data obtained during the runs were used to test a few data analysis algorithms, namely coalescing binaries and burst searches. The main improvements made on the detector during this year will be described, as well as the plans and activities foreseen in the coming years.
... 5506: physics of the extended narrow line region* Roberto Maiolino1, Ruggero Stanga1, Marco S... more ... 5506: physics of the extended narrow line region* Roberto Maiolino1, Ruggero Stanga1, Marco Salvati2, and José M. Rodriguez Espinosa3 1 ... Send offprint requests to: R. Maiolino * Based on observations made with the William Herschel Telescope, operated on the island of La ...
We report J, H, and K photometry of 86 stars in 40 elds in the northern hemisphere. The elds are ... more We report J, H, and K photometry of 86 stars in 40 elds in the northern hemisphere. The elds are smaller than or comparable to a 4 4 arcmin eld-of-view, and are roughly uniformly distributed over the sky, making them suitable for a homogeneous broadband calibration network for near-infrared panoramic detectors. K magnitudes range from 8.5 to 14, and J ?K colors from -0.1 to 1.2. The photometry is derived from a total of 3899 reduced images; each star has been measured, on average, 26.0 times per lter on 5.5 nights. Typical errors on the photometry are 0: m 012. Subject headings: methods: data analysis | techniques: photometric { 3 { { 4 {
One of the goal of the gravitational data wave analysts is the knowledge and the accurate estimat... more One of the goal of the gravitational data wave analysts is the knowledge and the accurate estimation of the noise power spectral density of the data taken by the detector, being it necessary in the detection algorithms. In this paper we showed how it is possible estimate the noise power spectral density of gravitational waves detectors using modern parametric techniques and how it is possible whiten the noise data before pass it to the algorithms for the gravitational waves detection. We report the analysis we made on data taken by Caltech 40-meter prototype interferometer to identify its noise power spectral density and to whiten the sequence of noise. We concentrate our study on data taken in November 1994, in particular we analyzed two frames of data: the 18nov94.2.frame and the 19nov94.2.frame. We show that it is possible to whiten these data, to a good degree of whiteness, using a high order whitening filter. Moreover we can choose to whiten only restricted band of frequencies around the region we are interested in, obtaining a higher level of whiteness. 04.80.Nn, 07.05Kf, 07.60Ly, 05.40Ca, 05.40C
The gravitational wave detector VIRGO aims at extending the detection band down to a few Hertz by... more The gravitational wave detector VIRGO aims at extending the detection band down to a few Hertz by isolating the mirrors of the interferometer from seismic noise. This result is achieved by hanging each mirror through an elastic suspension (Superattenuator), designed to filter mechanical vibrations in all the degrees of freedom. An experimental upper limit of the mirror residual seismic noise at a few Hertz is provided in this paper. This is lower than the thermal noise floor, expected to limit the antenna sensitivity in the low frequency range.
The knowledge of the noise power spectral density of an interferometric detector of gravitational... more The knowledge of the noise power spectral density of an interferometric detector of gravitational waves is fundamental for detection algorithms and for the analysis of the data. In this paper we address both the problem of identifying the noise power spectral density of interferometric detectors by parametric techniques and the problem of the whitening procedure of the sequence of data. We will concentrate the study on a power spectral density like that of the Italian-French detector VIRGO and we show that with a reasonable number of parameters we succeed in modelling a spectrum like the theoretical one of VIRGO, reproducing all of its features.
Nuclear Instruments & Methods in Physics Research Section A-accelerators Spectrometers Detectors and Associated Equipment, 2002
Low-power, ultra-high-vacuum compatible, non-contacting position sensors with nanometer resolutio... more Low-power, ultra-high-vacuum compatible, non-contacting position sensors with nanometer resolution and centimeter dynamic range have been developed, built and tested. They have been designed at Virgo as the sensors for low-frequency modal damping of Seismic Attenuation System chains in Gravitational Wave interferometers and sub-micron absolute mirror positioning. One type of these linear variable differential transformers (LVDTs) has been designed to be also insensitive to transversal displacement thus allowing 3D movement of the sensor head while still precisely reading its position along the sensitivity axis. A second LVDT geometry has been designed to measure the displacement of the vertical seismic attenuation filters from their nominal position. Unlike the commercial LVDTs, mostly based on magnetic cores, the LVDTs described here exert no force on the measured structure. r 2002 Elsevier Science B.V. All rights reserved. PACS: 04.80.Nn; 95.30.Sf; 95.55.Ym (H. Tariq). 0168-9002/02/$ -see front matter r 2002 Elsevier Science B.V. All rights reserved. PII: S 0 1 6 8 -9 0 0 2 ( 0 2 ) 0 0 8 0 2 -1
After a sequence of intermediate stages, the interferometer is now being used in the so-called re... more After a sequence of intermediate stages, the interferometer is now being used in the so-called recombined configuration. The input laser beam is spatially filtered by a 144 m long input mode-cleaner before being injected to the main interferometer. The main optics are suspended from so-called \sa s, which provide an excellent seismic isolation. The two 3 km long Fabry-Perot arm cavities are kept in resonance with the laser light, and the Michelson interferometer is held on the dark fringe. An automatic mirror alignment system based on the Anderson technique has been implemented for the arm cavities. The light leaving the dark port contains the gravitational wave signal; this light is filtered by an output mode-cleaner before being detected by a photo detector. This setup is the last step on the way to the final configuration, which will include power recycling.
Uploads
Papers by Ruggero Stanga