26,864 research outputs found
Virgo an interferometer for gravitational wave detection
No full textGravitational waves propagating from rapidly accelerating star masses can be detected by means of interferometric techniques. The Virgo detector is a Michelson interferometer, with two 3 km long Fabry-Perot cavities, that is going to be built in the countryside of Pisa (Italy). Principles of interferometric gravitational wave detection, and the main noise sources in the Virgo apparatus are treated. The Virgo optical scheme and its main components are also described. Finally, an overview on the status of works at the Virgo site is presented. © 2000 by the American College of Cardiology
The VIRGO experiment
No full textThe status of the VIRGO experiment, as of summer 2000 is presented: we report on the progress in the construction and the next steps are briefly illustrated
The VIRGO suspensions
No full textThe VIRGO suspensions are chains of passive mechanical filters designed to isolate the interferometer mirrors from seismic noise starting from a few Hz. In order to reduce the low-frequency swing of the mirror along the beam, an active control system, acting at the level of the suspension point, damps the main resonant modes of the system (all below 2.5 Hz). Another control loop, at the level of the optical payload, makes use of a digital camera monitoring the mirror position in all six degrees of freedom. Its main goal is to decrease the rms angular displacements of the mirror, on a time scale of several minutes, down to less than I murad. All the seven suspensions of the VIRGO central interferometer are presently in operation, while the assembly of the last two, for the terminal mirrors, is in progress, The design and performance of the system are described in this paper
Sensing and control in Virgo experiment
No full textThe gravitational wave detector Virgo is presently under commissioning. A large part of the last year has been spent for control activities, such as the longitudinal locking. This work has been carried out with steps of increasing complexity: locking a simple Fabry-Perot cavity, then a Michelson interferometer with Fabry-Perot cavities in both arms, and finally recycling the light beam into the interferometer
Calibration of the VIRGO central interferometer
No full textThis paper describes the calibration procedures developed for the commissioning of the VIRGO central interferometer, as well as their main results obtained during the engineering runs that occurred during that phase. The issue of the detector response monitoring is also addressed, and a preliminary test to produce reconstructed data is reported
Status of Virgo
No full textIn this paper, we present the status of the VIRGO interferometer, the French–
Italian gravitational wave detector. During the last two years the construction
of the apparatus has been completed. At the same time, the commissioning
of the detector central part, the VIRGO central interferometer, has been used
to test all the technical solutions and in particular the most original part: the
seismic isolation system. In the next few months the commissioning of the
whole detector will start with the alignment and the locking of one of the two
3 km long Fabry–Perot cavities
Search for gravitational-lensing signatures in the full third observing run of the LIGO–Virgo network
No full textThis material is part of several data products associated with the publication "Search for gravitational-lensing signatures in the full third observing run of the LIGO–Virgo network" from the LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration. For more information, see the paper (arXiv) and the related material linked from this page.
Data release
This data release contains plotting scripts, jupyter notebooks and datasets for the figures / tables in the aforementioned paper. Each script/notebook have detailed instructions and comments.
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Search for non-Gaussian events in the data of the VIRGO E4 engineering run
No full textThis work is a first attempt to search for glitch events in the data of the VIRGO Central Interferometer (CITF). In the first step, using simple algorithms, we searched for strong glitches in the interferometer's output photodiodes signals over the three days of data of the last engineering run. In the second step, we focused on 10 hours of data taken when the interferometer was locked and stable. The events found in the dark-fringe signal during this period are all within 3 rms of the mean output value of each algorithm and are, in some cases, linked to a beat between the powerline 50 Hz contamination and a 43.7 Hz line that comes from injection-system components. The main conclusions are that, at this level of analysis, the algorithms used have found no strong glitch-like events in the dark-fringe signal of VIRGO and that removing spectral lines like the 50 Hz is essential to further investigation
The antiseismic suspension for the VIRGO project
No full textGravitational waves propagating from rapidly accelerating star masses can be detected by means of interferometric techniques. Several interferometric antennas are presently under construction around the world with the aim of gravitational waves detection in the frequency range starting from a few tens of Hz to a few kHz. In the low frequency region (below a few tens of Hz) their detection is limited by seismic noise which can mask the weak signal induced by a gravitational wave impinging on a suspended mirror. In order to overcome this limitation, the VIRGO collaboration has developed and built a sophisticated suspension system to isolate the optical components from the seismic noise. This mechanical system, called SuperAttenuator, is able to inhibit the transmission of any mechanical disturbances starting from about 4 Hz thus extending the detection band in the low frequency region
Advanced Virgo+ status and future perspectives
No full textThe Virgo detector contributed to the observations in the O3 observing run and increased its sensitivity from the
initial 46 up to 60 Mpc during the run. The detector has undergone to a series of improvements since the end of
the O3 observing run in view of O4, as the implementation of an additional recycling cavity at the output of the
interferometer – the Signal Recycling cavity (SRC) – to broaden the sensitivity band, the Frequency Dependent
Squeezing (FDS) to reduce quantum noise at all frequencies, and a new higher power laser.
Some criticality have emerged mainly due to the presence in Virgo of marginally stable recycling cavities with
respect to the stable recycling cavities present in the LIGO detectors, which increases the difficulty in controlling
the interferometer in presence of defects as those introduced by the high power on the mirrors. This resulted
in a delayed joining the O4 run due to a longer than expected commissioning phase. At present the detector is
running with a lower laser power (and a lower sensitivity w.r.t. the project design).
A new stop of about 2 yr is planned between O4 and O5 starting in 2027, to implement new upgrades (phase
II). To improve the stability of the interferometer, we are considering a large upgrade to introduce stable cavities
and this will imply heavy infrastructural works also with the minimal design. The aim is to reach a Binary
Neutron Star (BNS) sensitivity larger than 100 Mpc.
Plans are being made for the post-O5 period as a bridge between 2nd and 3rd generation detectors and a new
collaborative effort has born under the name of Virgo nEXT with the aim to keep and push the infrastructure
and maintain alive the communit
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