The Advanced Virgo (AdV) sensitivity might be influenced by the effects of environmental noise, in particular magnetic noise (MN). In order to show the impact on the gravitational-wave strain signal h(t) and on the AdV sensitivity, we must understand the coupling between the environmental magnetic activity and the strain. The relationship between the environmental noise - measured by a physical environment monitor (PEM) - and h(t) is investigated using injection studies, where an intentional stimulus is introduced and the responses of both PEM sensors and the instrument are analyzed. We also present the most outstanding measurements and results obtained from both the characterization and the mitigation studies of the environmental MN. Results show that MN does not affect AdV sensitivity up to $\approx 100$ Mpc in BNS range.
As the sensitivities of LIGO, Virgo and KAGRA detectors improve, calibration of the interferometers output is becoming more and more important and may impact scientific results. For the observing run O3, Virgo used for the first time photon calibrators (PCal) to calibrate the interferometer, using radiation pressure of a modulated auxiliary laser beam impinging on the Advanced Virgo end mirrors. Those optical devices, also used in LIGO, are now the calibration reference for the global gravitational wave detectors network. The intercalibration of LIGO and Virgo PCals, based on the same absolute…
On September 2015, a century after Einstein's predictions of their existence, the first gravitational waves (GWs) direct detection was performed by LIGO. On August 17, 2017, the two Advanced LIGO and the Advanced Virgo interferometers detected a GW produced by two merging neutron stars. The subsequent localization of the source in the sky, thanks to the presence of a third detector, led to the detection of the electromagnetic counterpart and follow-up of the event by roughly 70 electromagnetic and neutrino telescopes. After the first two data taking runs (O1 and O2), the LIGO-Virgo network det…
Magnetars are neutron stars with exceptionally strong dipole magnetic fields which are observed to display a range of x-ray flaring behavior, but the flaring mechanism is not well understood. The third observing run of Advanced LIGO and Virgo extended from April 1, 2019 to March 27, 2020, and contained x-ray flares from known magnetar SGR 1935+2154, as well as the newly-discovered magnetar, Swift J1818-1607. We search for gravitational waves coincident with these magnetar flares with minimally modeled, coherent searches which specifically target both short-duration gravitational waves produced…
A new instrumented baffle was installed in Spring 2021 at Virgo surrounding the suspended mirror in the input mode cleaner triangular cavity. It serves as a demonstrator of the technology designed to instrument the baffles in the main arms in the near future. We present, for the first time, results on the measured scattered light distribution inside the cavity as determined by the new device using data collected between May and July 2021, with Virgo in commissioning phase and operating with an input laser power in the cavity of 28.5~W. The sensitivity of the baffle is discussed and the data is…
The third observing run of Advanced LIGO and Advanced Virgo took place between April 2019 and March 2020 and resulted in dozens of gravitational-wave candidates, many of which are now published as confident detections. A crucial requirement of the third observing run has been the rapid identification and public reporting of compact binary mergers, which enabled massive followup observation campaigns with electromagnetic and neutrino observatories. PyCBC Live is a low-latency search for compact binary mergers based on frequency-domain matched filtering, which has been used during the second and…
The field of gravitational-wave astronomy has been opened up by gravitational-wave observations made with interferometric detectors. This review surveys the current state-of-the-art in gravitational-wave detectors and data analysis methods currently used by the Laser Interferometer Gravitational-Wave Observatory in the United States and the Virgo Observatory in Italy. These analysis methods will also be used in the recently completed KAGRA Observatory in Japan. Data analysis algorithms are developed to target one of four classes of gravitational waves. Short duration, transient sources include…
Advanced Virgo end benches were a significant source of scattered light noise during the third observing run that lasted from April 1 2019 until March 27 2020. We describe how that noise could be subtracted using auxiliary channels during the online strain data reconstruction. We model in detail the scattered light noise coupling and demonstrate that further noise subtraction can be achieved. We also show that the fitted model parameters can be used to optically characterized the interferometer and in particular provide a novel way of establishing an absolute calibration of the detector strain…
Reducing the Virgo site infrastructure noise in preparation of the O4 observing run
European Gravitational Observatory (EGO)（欧洲引力观测站）；INFN, Sezione di Pisa（意大利国家核物理研究所比萨分部）；Università di Pisa（比萨大学）；INFN, Sezione di Roma（意大利国家核物理研究所罗马分部）；INFN, Sezione di Firenze（意大利国家核物理研究所佛罗伦萨分部）；Università di Firenze（佛罗伦萨大学）；Università degli Studi di Urbino “Carlo Bo”（乌尔比诺卡尔洛·博大学）
The Instrumented Baffle at the Input Mode Cleaner of Advanced Virgo Plus: Four years of Successful Operation as a Monitor of Stray Light
Institut de Física d’Altes Energies (IFAE), The Barcelona Institute of Science and Technology（高能物理研究所，巴塞罗那科学技术学院）；Catalan Institution for Research and Advanced Studies (ICREA)（加泰罗尼亚研究与高级研究学院）
研究评估了先进维格 Plus 输入模式清洁器中仪器化挡板四年的性能，展示了其在监控腔内 stray 光和激光稳定性方面的有效性，且未对干涉仪正常运行造成干扰。
We describe the methods used to construct the aligned-spin template bank of gravitational waveforms used by the GstLAL-based inspiral pipeline to analyze data from the second observing run of Advanced LIGO and the first observing run of advanced Virgo. The bank expands upon the parameter space covered during the first observing run, including coverage for merging compact binary systems with total mass between 2 $\mathrm{M}_{\odot}$ and 400 $\mathrm{M}_{\odot}$ and mass ratios between 1 and 97.988. Thus the systems targeted include merging neutron star-neutron star systems, neutron star-black h…
Data from current gravitational wave detectors contains a high rate of transient noise (glitches) that can trigger false detections and obscure true astrophysical events. Existing noise-detection algorithms largely rely on model-based methods that may miss noise transients unwitnessed by auxiliary sensors or with exotic morphologies. We propose the Unicorn Multi-window Anomaly-detection Pipeline (UniMAP): a model-free algorithm to identify and characterize transient noise leveraging the Temporal Outlier Factor (TOF) via a multi-window data-resampling scheme. We show this windowing scheme exten…
Gravitational-wave observations of binary neutron star mergers and their electromagnetic counterparts provide an independent measurement of the Hubble constant, $H_0$, through the standard-sirens approach. Current methods of determining $H_0$, such as measurements from the early universe and the local distance ladder, are in tension with one another. If gravitational waves are to break this tension a thorough understanding of systematic uncertainty for gravitational-wave observations is required. To accurately estimate the properties of gravitational-wave signals measured by LIGO and Virgo, we…
A methodology of adaptive time series analysis, based on Empirical Mode Decomposition (EMD), and on its time varying version tvf-EMD has been applied to strain data from the gravitational wave interferometer (IFO) Virgo in order to characterise scattered light noise affecting the sensitivity of the IFO in the detection frequency band. Data taken both during hardware injections, when a part of the IFO is put in oscillation for detector characterisation purposes, and during periods of science mode, when the IFO is fully locked and data are used for the detection of gravitational waves, were anal…
Sources of geophysical noise (such as wind, sea waves and earthquakes) or of anthropogenic noise (nearby activities, road traffic, etc.) impact ground-based gravitational-wave (GW) interferometric detectors, causing transient sensitivity worsening and gaps in data taking. During the one year-long third Observing Run (O3: from April 01, 2019 to March 27, 2020), the Virgo Collaboration collected a large dataset, which has been used to study the response of the Advanced Virgo detector to a variety of environmental conditions. We correlated environmental parameters to global detector performance, …
Data acquired by the Virgo interferometer during the second part of the O3 scientific run, referred to as O3b, were analysed with the aim of characterising the onset and time evolution of scattered light noise in connection with the variability of microseismic noise in the environment surrounding the detector. The adaptive algorithm used, called pytvfemd, is suitable for the analysis of time series which are both nonlinear and nonstationary. It allowed to obtain the first oscillatory mode of the differential arm motion degree of freedom of the detector during days affected by scattered light n…
Fluctuations of gravitational forces cause so-called Newtonian noise (NN) in gravitational-wave (GW) detectors which is expected to limit their low-frequency sensitivity in upcoming observing runs. Seismic NN is produced by seismic waves passing near a detector's suspended test masses. It is predicted to be the strongest contribution to NN. Modeling this contribution accurately is a major challenge. Arrays of seismometers were deployed at the Virgo site to characterize the seismic field near the four test masses. In this paper, we present results of a spectral analysis of the array data from o…
Machine learning for gravitational-wave detection: surrogate Wiener filtering for the prediction and optimized cancellation of Newtonian noise at Virgo
Applying deep neural networks to the detection and space parameter estimation of compact binary coalescence with a network of gravitational wave detectors
PyCBC Live Search for Compact Binary Mergers in Advanced LIGO and Virgo's Fourth Observing Run
University of Maryland, College Park（马里兰大学帕克分校）；Institute for Cosmology and Gravitation, University of Portsmouth（朴茨茅斯宇宙学与引力研究所，朴茨茅斯大学）；Université Paris-Saclay, CNRS/IN2P3, IJCLab（巴黎-萨克雷大学，法国国家科学研究中心/欧洲核子研究学院，IJCLab）；Instituto Galego de Física de Altas Enerxías, Universidade de Santiago de Compostela（加利西亚高能物理研究所，圣地亚哥-德孔波斯特拉大学）
本文改进了 PyCBC Live 低延迟搜索管道，用于 LIGO-Virgo-KAGRA 第四次观测运行（O4），通过增强排名统计量、优化信噪比恢复和实现预警搜索，将灵敏度提高 1.7-2.3 倍，并实现 2.5-3.5 秒延迟的并合前预警。
Searches After Gravitational-waves Using ARizona Observatories (SAGUARO): System Overview and First Results from Advanced LIGO/Virgo's Third Observing Run
