Showing papers by "Enrico Calloni published in 2012"
Bangalore Suryanarayana Sathyaprakash1, M. R. Abernathy2, Fausto Acernese3, P. Ajith4 +222 more•Institutions (38)
TL;DR: The advanced interferometer network will herald a new era in observational astronomy, and there is a very strong science case to go beyond the advanced detector network and build detectors that operate in a frequency range from 1 Hz to 10 kHz, with sensitivity a factor 10 better in amplitude as discussed by the authors.
Abstract: The advanced interferometer network will herald a new era in observational astronomy. There is a very strong science case to go beyond the advanced detector network and build detectors that operate in a frequency range from 1 Hz to 10 kHz, with sensitivity a factor 10 better in amplitude. Such detectors will be able to probe a range of topics in nuclear physics, astronomy, cosmology and fundamental physics, providing insights into many unsolved problems in these areas.
441 citations
TL;DR: Virgo as discussed by the authors is a very large Michelson interferometer with 3 km-long arms, built at Cascina, near Pisa (Italy), with a detailed description of all its different elements is given.
Abstract: This paper presents a complete description of Virgo, the French-Italian gravitational wave detector. The detector, built at Cascina, near Pisa (Italy), is a very large Michelson interferometer, with 3 km-long arms. In this paper, following a presentation of the physics requirements, leading to the specifications for the construction of the detector, a detailed description of all its different elements is given. These include civil engineering infrastructures, a huge ultra-high vacuum (UHV) chamber (about 6000 cubic metres), all of the optical components, including high quality mirrors and their seismic isolating suspensions, all of the electronics required to control the interferometer and for signal detection. The expected performances of these different elements are given, leading to an overall sensitivity curve as a function of the incoming gravitational wave frequency. This description represents the detector as built and used in the first data-taking runs. Improvements in different parts have been and continue to be performed, leading to better sensitivities. These will be detailed in a forthcoming paper.
321 citations
TL;DR: In this paper, the authors report on a search for gravitational waves from coalescing compact binaries using LIGO and Virgo observations between July 7, 2009, and October 20, 2010.
Abstract: We report on a search for gravitational waves from coalescing compact binaries using LIGO and Virgo observations between July 7, 2009, and October 20, 2010. We searched for signals from binaries with total mass between 2 and 25M(circle dot); this includes binary neutron stars, binary black holes, and binaries consisting of a black hole and neutron star. The detectors were sensitive to systems up to 40 Mpc distant for binary neutron stars, and further for higher mass systems. No gravitational-wave signals were detected. We report upper limits on the rate of compact binary coalescence as a function of total mass, including the results from previous LIGO and Virgo observations. The cumulative 90% confidence rate upper limits of the binary coalescence of binary neutron star, neutron star-black hole, and binary black hole systems are 1.3 x 10(-4), 3.1 x 10(-5), and 6.4 x 10(-6) Mpc(-3) yr(-1), respectively. These upper limits are up to a factor 1.4 lower than previously derived limits. We also report on results from a blind injection challenge.
229 citations
TL;DR: The results of a search for gravitational waves associated with 154 gamma-ray bursts (GRBs) were detected by satellite-based gamma ray experiments in 2009-2010, during the sixth LIGO science run and the second and third Virgo science runs as mentioned in this paper.
Abstract: We present the results of a search for gravitational waves associated with 154 gamma-ray bursts (GRBs) that were detected by satellite-based gamma-ray experiments in 2009-2010, during the sixth LIGO science run and the second and third Virgo science runs. We perform two distinct searches: a modeled search for coalescences of either two neutron stars or a neutron star and black hole, and a search for generic, unmodeled gravitational-wave bursts. We find no evidence for gravitational-wave counterparts, either with any individual GRB in this sample or with the population as a whole. For all GRBs we place lower bounds on the distance to the progenitor, under the optimistic assumption of a gravitational-wave emission energy of 10–2 M ☉ c 2 at 150 Hz, with a median limit of 17 Mpc. For short-hard GRBs we place exclusion distances on binary neutron star and neutron-star-black-hole progenitors, using astrophysically motivated priors on the source parameters, with median values of 16 Mpc and 28 Mpc, respectively. These distance limits, while significantly larger than for a search that is not aided by GRB satellite observations, are not large enough to expect a coincidence with a GRB. However, projecting these exclusions to the sensitivities of Advanced LIGO and Virgo, which should begin operation in 2015, we find that the detection of gravitational waves associated with GRBs will become quite possible.
149 citations
TL;DR: In this paper, a low-latency analysis pipeline was used to identify and localize GW event candidates and to reconstruct maps of possible sky locations, and a catalog of nearby galaxies and Milky Way globular clusters were used to select the most promising sky positions to be imaged.
Abstract: Aims. A transient astrophysical event observed in both gravitational wave (GW) and electromagnetic (EM) channels would yield rich scientific rewards. A first program initiating EM follow-ups to possible transient GW events has been developed and exercised by the LIGO and Virgo community in association with several partners. In this paper, we describe and evaluate the methods used to promptly identify and localize GW event candidates and to request images of targeted sky locations. Methods. During two observing periods (Dec. 17, 2009 to Jan. 8, 2010 and Sep. 2 to Oct. 20, 2010), a low-latency analysis pipeline was used to identify GW event candidates and to reconstruct maps of possible sky locations. A catalog of nearby galaxies and Milky Way globular clusters was used to select the most promising sky positions to be imaged, and this directional information was delivered to EM observatories with time lags of about thirty minutes. A Monte Carlo simulation has been used to evaluate the low-latency GW pipeline's ability to reconstruct source positions correctly. Results. For signals near the detection threshold, our low-latency algorithms often localized simulated GW burst signals to tens of square degrees, while neutron star/neutron star inspirals and neutron star/black hole inspirals were localized to a few hundred square degrees. Localization precision improves for moderately stronger signals. The correct sky location of signals well above threshold and originating from nearby galaxies may be observed with similar to 50% or better probability with a few pointings of wide-field telescopes.
120 citations
TL;DR: In this paper, the authors presented results from a search for gravitational-wave bursts in the data collected by the LIGO and Virgo detectors between July 7, 2009 and October 20, 2010.
Abstract: We present results from a search for gravitational-wave bursts in the data collected by the LIGO and Virgo detectors between July 7, 2009 and October 20, 2010: data are analyzed when at least two of the three LIGO-Virgo detectors are in coincident operation, with a total observation time of 207 days. The analysis searches for transients of duration less than or similar to 1 s over the frequency band 64-5000 Hz, without other assumptions on the signal waveform, polarization, direction or occurrence time. All identified events are consistent with the expected accidental background. We set frequentist upper limits on the rate of gravitational-wave bursts by combining this search with the previous LIGO-Virgo search on the data collected between November 2005 and October 2007. The upper limit on the rate of strong gravitational-wave bursts at the Earth is 1.3 events per year at 90% confidence. We also present upper limits on source rate density per year and Mpc(3) for sample populations of standard-candle sources. As in the previous joint run, typical sensitivities of the search in terms of the root-sum-squared strain amplitude for these waveforms lie in the range similar to 5 x 10(-22) Hz(-1/2) to similar to 1 x 10(-20) Hz(-1/2). The combination of the two joint runs entails the most sensitive all-sky search for generic gravitational-wave bursts and synthesizes the results achieved by the initial generation of interferometric detectors.
113 citations
TL;DR: The results of a search for gravitational waves associated with 154 gamma-ray bursts (GRBs) that were detected by satellite-based gamma ray experiments in 2009-2010, during the sixth LIGO science run and the second and third Virgo science runs are presented in this article.
Abstract: We present the results of a search for gravitational waves associated with 154 gamma-ray bursts (GRBs) that were detected by satellite-based gamma-ray experiments in 2009-2010, during the sixth LIGO science run and the second and third Virgo science runs. We perform two distinct searches: a modeled search for coalescences of either two neutron stars or a neutron star and black hole; and a search for generic, unmodeled gravitational-wave bursts. We find no evidence for gravitational-wave counterparts, either with any individual GRB in this sample or with the population as a whole. For all GRBs we place lower bounds on the distance to the progenitor, under the optimistic assumption of a gravitational-wave emission energy of 10^-2 M c^2 at 150 Hz, with a median limit of 17 Mpc. For short hard GRBs we place exclusion distances on binary neutron star and neutron star-black hole progenitors, using astrophysically motivated priors on the source parameters, with median values of 16 Mpc and 28 Mpc respectively. These distance limits, while significantly larger than for a search that is not aided by GRB satellite observations, are not large enough to expect a coincidence with a GRB. However, projecting these exclusions to the sensitivities of Advanced LIGO and Virgo, which should begin operation in 2015, we find that the detection of gravitational waves associated with GRBs will become quite possible.
93 citations
TL;DR: In this article, the first low-latency search for gravitational-waves from binary inspirals in LIGO and Virgo data was conducted, and the resulting triggers were sent to electromagnetic observatories for followup.
Abstract: Aims: The detection and measurement of gravitational-waves from coalescing neutron-star binary systems is an important science goal for ground-based gravitational-wave detectors. In addition to emitting gravitational-waves at frequencies that span the most sensitive bands of the LIGO and Virgo detectors, these sources are also amongst the most likely to produce an electromagnetic counterpart to the gravitational-wave emission. A joint detection of the gravitational-wave and electromagnetic signals would provide a powerful new probe for astronomy. Methods: During the period between September 19 and October 20, 2010, the first low-latency search for gravitational-waves from binary inspirals in LIGO and Virgo data was conducted. The resulting triggers were sent to electromagnetic observatories for followup. We describe the generation and processing of the low-latency gravitational-wave triggers. The results of the electromagnetic image analysis will be described elsewhere. Results: Over the course of the science run, three gravitational-wave triggers passed all of the low-latency selection cuts. Of these, one was followed up by several of our observational partners. Analysis of the gravitational-wave data leads to an estimated false alarm rate of once every 6.4 days, falling far short of the requirement for a detection based solely on gravitational-wave data.
92 citations
TL;DR: In this paper, the authors present examples from the joint LIGO-GEO-Virgo GW searches to show how well noise transients and narrow spectral lines have been identified and excluded from the Virgo data.
Abstract: Between 2007 and 2010 Virgo collected data in coincidence with the LIGO and GEO gravitational-wave (GW) detectors. These data have been searched for GWs emitted by cataclysmic phenomena in the universe, by non-axisymmetric rotating neutron stars or from a stochastic background in the frequency band of the detectors. The sensitivity of GW searches is limited by noise produced by the detector or its environment. It is therefore crucial to characterize the various noise sources in a GW detector. This paper reviews the Virgo detector noise sources, noise propagation, and conversion mechanisms which were identified in the three first Virgo observing runs. In many cases, these investigations allowed us to mitigate noise sources in the detector, or to selectively flag noise events and discard them from the data. We present examples from the joint LIGO-GEO-Virgo GW searches to show how well noise transients and narrow spectral lines have been identified and excluded from the Virgo data. We also discuss how detector characterization can improve the astrophysical reach of GW searches.
90 citations
TL;DR: In this article, the authors present examples from the joint LIGO-GEO-Virgo GW searches to show how well noise transients and narrow spectral lines have been identified and excluded from the Virgo data.
Abstract: Between 2007 and 2010 Virgo collected data in coincidence with the LIGO and GEO gravitational-wave (GW) detectors. These data have been searched for GWs emitted by cataclysmic phenomena in the universe, by non-axisymmetric rotating neutron stars or from a stochastic background in the frequency band of the detectors. The sensitivity of GW searches is limited by noise produced by the detector or its environment. It is therefore crucial to characterize the various noise sources in a GW detector. This paper reviews the Virgo detector noise sources, noise propagation, and conversion mechanisms which were identified in the three first Virgo observing runs. In many cases, these investigations allowed us to mitigate noise sources in the detector, or to selectively flag noise events and discard them from the data. We present examples from the joint LIGO-GEO-Virgo GW searches to show how well noise transients and narrow spectral lines have been identified and excluded from the Virgo data. We also discuss how detector characterization can improve the astrophysical reach of gravitational-wave searches.
74 citations
TL;DR: In this article, the first multi-wavelength follow-up observations of two candidate gravitational-wave (GW) transient events recorded by LIGO and Virgo in their 2009-2010 science run are presented.
Abstract: We present the first multi-wavelength follow-up observations of two candidate gravitational-wave (GW) transient events recorded by LIGO and Virgo in their 2009-2010 science run. The events were selected with low latency by the network of GW detectors and their candidate sky locations were observed by the Swift observatory. Image transient detection was used to analyze the collected electromagnetic data, which were found to be consistent with background. Off-line analysis of the GW data alone has also established that the selected GW events show no evidence of an astrophysical origin; one of them is consistent with background and the other one was a test, part of a "blind injection challenge". With this work we demonstrate the feasibility of rapid follow-ups of GW transients and establish the sensitivity improvement joint electromagnetic and GW observations could bring. This is a first step toward an electromagnetic follow-up program in the regime of routine detections with the advanced GW instruments expected within this decade. In that regime multi-wavelength observations will play a significant role in completing the astrophysical identification of GW sources. We present the methods and results from this first combined analysis and discuss its implications in terms of sensitivity for the present and future instruments.
Bangalore Suryanarayana Sathyaprakash1, M. R. Abernathy2, Fausto Acernese3, P. Ajith4 +222 more•Institutions (38)
TL;DR: The advanced interferometer network will herald a new era in observational astronomy, and there is a very strong science case to go beyond the advanced detector network and build detectors that operate in a frequency range from 1 Hz-10 kHz, with sensitivity a factor ten better in amplitude as mentioned in this paper.
Abstract: The advanced interferometer network will herald a new era in observational astronomy. There is a very strong science case to go beyond the advanced detector network and build detectors that operate in a frequency range from 1 Hz-10 kHz, with sensitivity a factor ten better in amplitude. Such detectors will be able to probe a range of topics in nuclear physics, astronomy, cosmology and fundamental physics, providing insights into many unsolved problems in these areas.
TL;DR: In this article, the first multi-wavelength follow-up observations of two candidate gravitational-wave (GW) transient events recorded by LIGO and Virgo in their 2009-2010 science run are presented.
Abstract: We present the first multi-wavelength follow-up observations of two candidate gravitational-wave (GW) transient events recorded by LIGO and Virgo in their 2009-2010 science run. The events were selected with low latency by the network of GW detectors (within less than 10 minutes) and their candidate sky locations were observed by the Swift observatory (within 12 hr). Image transient detection was used to analyze the collected electromagnetic data, which were found to be consistent with background. Off-line analysis of the GW data alone has also established that the selected GW events show no evidence of an astrophysical origin; one of them is consistent with background and the other one was a test, part of a "blind injection challenge." With this work we demonstrate the feasibility of rapid follow-ups of GW transients and establish the sensitivity improvement joint electromagnetic and GW observations could bring. This is a first step toward an electromagnetic follow-up program in the regime of routine detections with the advanced GW instruments expected within this decade. In that regime, multi-wavelength observations will play a significant role in completing the astrophysical identification of GW sources. We present the methods and results from this first combined analysis and discuss its implications in terms of sensitivity for the present and future instruments.
15 Mar 2012
TL;DR: In this article, the authors summarize the sensitivity achieved by the LIGO and Virgo detectors for low-mass compact binary coalescence (CBC) searches during the LigO's sixth science run and the Virgo's second and third science runs.
Abstract: We summarize the sensitivity achieved by the LIGO and Virgo gravitational wave detectors for low-mass compact binary coalescence (CBC) searches during LIGO's sixth science run and Virgo's second and third science runs. We present strain noise power spectral densities (PSDs) which are representative of the typical performance achieved by the detectors in these science runs. The data presented here and in the accompanying web-accessible data files are intended to be released to the public as a summary of detector performance for low-mass CBC searches during S6 and VSR2-3.
TL;DR: In this paper, the authors presented the first joint search for a stochastic background using data from the LIGO and Virgo interferometers in a frequency band of 600-1000 Hz.
Abstract: A stochastic background of gravitational waves is expected to arise from a superposition of many incoherent sources of gravitational waves, of either cosmological or astrophysical origin. This background is a target for the current generation of ground-based detectors. In this article we present the first joint search for a stochastic background using data from the LIGO and Virgo interferometers. In a frequency band of 600-1000 Hz, we obtained a 95% upper limit on the amplitude of ΩGW(f)=Ω3(f/900 Hz)3, of Ω3<0.32, assuming a value of the Hubble parameter of h100=0.71. These new limits are a factor of seven better than the previous best in this frequency band.
TL;DR: In this article, the authors presented the results of a weakly modeled burst search for gravitational waves from mergers of non-spinning intermediate mass black holes (IMBH) in the total mass range 100--450 solar masses and with the component mass ratios between 1:1 and 4:1.
Abstract: We present the results of a weakly modeled burst search for gravitational waves from mergers of non-spinning intermediate mass black holes (IMBH) in the total mass range 100--450 solar masses and with the component mass ratios between 1:1 and 4:1. The search was conducted on data collected by the LIGO and Virgo detectors between November of 2005 and October of 2007. No plausible signals were observed by the search which constrains the astrophysical rates of the IMBH mergers as a function of the component masses. In the most efficiently detected bin centered on 88+88 solar masses, for non-spinning sources, the rate density upper limit is 0.13 per Mpc^3 per Myr at the 90% confidence level.
TL;DR: In this paper, the results of the first search for gravitational wave bursts associated with high energy neutrinos were presented, which could reveal new, hidden sources that are not observed by conventional photon astronomy, particularly at high energy.
Abstract: We present the results of the first search for gravitational wave bursts associated with high energy neutrinos. Together, these messengers could reveal new, hidden sources that are not observed by conventional photon astronomy, particularly at high energy. Our search uses neutrinos detected by the underwater neutrino telescope ANTARES in its 5 line configuration during the period January - September 2007, which coincided with the fifth and first science runs of LIGO and Virgo, respectively. The LIGO-Virgo data were analysed for candidate gravitational-wave signals coincident in time and direction with the neutrino events. No significant coincident events were observed. We place limits on the density of joint high energy neutrino - gravitational wave emission events in the local universe, and compare them with densities of merger and core-collapse events.
01 Feb 2012
TL;DR: In this article, the authors present a survey of the state-of-the-art methods to solve the problem of how to find the optimal solution for a given set of problems.
Abstract: T. ACCADIA12, F. ACERNESE6ac, F. ANTONUCCI9a, K. G. ARUN11, P. ASTONE9a, G. BALLARDIN2, F. BARONE6ac, M. BARSUGLIA1, TH. S. BAUER14a, M.G. BEKER14a, A. BELLETOILE12, S. BIGOTTA8ab, S. BIRINDELLI15a, M. BITOSSI8a, M. A. BIZOUARD11, M. BLOM14a, C. BOCCARA3, F. BONDU15b, L. BONELLI8ab, R. BONNAND13, V. BOSCHI8a, L. BOSI7a, B. BOUHOU1, S. BRACCINI8a, C. BRADASCHIA8a, A. BRILLET15a, V. BRISSON11, R. BUDZYŃSKI17b, T. BULIK17cd, H. J. BULTEN14ab, D. BUSKULIC12, C. BUY1, G. CAGNOLI4a, E. CALLONI6ab, E. CAMPAGNA4ab, B. CANUEL2, F. CARBOGNANI2, F. CAVALIER11, R. CAVALIERI2, G. CELLA8a, E. CESARINI4b, E. CHASSANDE-MOTTIN1, A. CHINCARINI5, F. CLEVA15a, E. COCCIA10ab, C. N. COLACINO8a, J. COLAS2, A. COLLA9ab, M. COLOMBINI9b, A. CORSI9a, J.-P. COULON15a, E. CUOCO2, S. D’ANTONIO10a, V. DATTILO2, M. DAVIER11, R. DAY2, R. DE ROSA6ab, M. DEL PRETE8ac, L. DI FIORE6a, A. DI LIETO8ab, M. DI PAOLO EMILIO10ac,∗, A. DI VIRGILIO8a, A. DIETZ12, M. DRAGO16cd, V. FAFONE10ab, I. FERRANTE8ab, F. FIDECARO8ab, I. FIORI2, R. FLAMINIO13, J.-D. FOURNIER15a, J. FRANC13, S. FRASCA9ab, F. FRASCONI8a,
01 Feb 2012
01 Jun 2012
TL;DR: The NoEMi (Noise Frequency Event Miner) framework as mentioned in this paper exploits some of the algorithms implemented for the continuous gravitational wave (CW) studies to identify, on a daily basis, the frequency lines observed in the Virgo science data and in a subset of the environmental sensors, looking for lines that match in frequency.
Abstract: The data collected by a gravitational wave interferometer are inevitably affected by instrumental artefacts and environmental disturbances. In particular, for continuous gravitational wave (CW) studies it is important to detect narrow-band disturbances (the so-called "noise lines") during science runs, and to help scientists to identify and possibly remove or mitigate their sources. The NoEMi (Noise Frequency Event Miner) framework exploits some of the algorithms implemented for the CW search to identify, on a daily basis, the frequency lines observed in the Virgo science data and in a subset of the environmental sensors, looking for lines that match in frequency. A line tracker algorithm reconstructs the lines over time, and stores them in a database, which is made accesible via a web interface. We describe the workflow of NoEMi, providing examples of its use for the investigation of noise lines in past Virgo runs (VSR2, VSR3) and in the most recent run (VSR4).
TL;DR: In this paper, a rigorous analysis of experimental data is reported, the results are discussed and compared with theoretical predictions based on Lifshitz theory of dispersion forces, and the BCS formula for the optical conductivity of superconductors.
Abstract: The ALADIN experiment aims at observing how the critical magnetic field of a superconducting aluminum film is modified, when it constitutes one of the reflecting surfaces of a Casimir cavity. If successful, such an observation would reveal the influence of vacuum energy on the superconducting phase transition. In this paper, a rigorous analysis of experimental data is reported, the results are discussed and compared with theoretical predictions based on Lifshitz theory of dispersion forces, and the BCS formula for the optical conductivity of superconductors. Thanks to this rigorous analysis, it can now be asserted that in the region of energy where it is expected that Casimir energy is comparable with condensation energy and the deviations of critical field from BCS formula to be not negligible, an anomalous behavior is found.
01 May 2012
TL;DR: In this paper, the results of a weakly modeled burst search for gravitational waves from mergers of nonspinning intermediate mass black holes in the total mass range 100-450 M-circle dot and with the component mass ratios between 1: and 4:1 were presented.
Abstract: We present the results of a weakly modeled burst search for gravitational waves from mergers of nonspinning intermediate mass black holes in the total mass range 100-450 M-circle dot and with the component mass ratios between 1: and 4:1. The search was conducted on data collected by the LIGO and Virgo detectors between November of 2005 and October of 2007. No plausible signals were observed by the search which constrains the astrophysical rates of the intermediate mass black holes mergers as a function of the component masses. In the most efficiently detected bin centered on 88 + 88 M-circle dot, for nonspinning sources, the rate density upper limit is 0.13 per Mpc(3) per Myr at the 90% confidence level.
TL;DR: Abadie et al. as mentioned in this paper search for gravitational waves from binary black hole inspiral, merger, and ringdown, Phys. Rev. D 83, 122005 (2011).
Abstract: Original Article: J. Abadie et al. (LIGO Scientific Collaboration, Virgo Collaboration), Search for gravitational waves from binary black hole inspiral, merger, and ringdown, Phys. Rev. D 83, 122005 (2011).
TL;DR: In this article, an attempt is made to measure the attenuation of emitted noise at the ITF and correlate it to the distance from the source and to seismic attenuation models in soil.
Abstract: The Virgo gravitational wave detector is an interferometer (ITF) with 3km arms located in Pisa, Italy. From July to October 2010, Virgo performed its third science run (VSR3) in coincidence with the LIGO detectors. Despite several techniques adopted to isolate the interferometer from the environment, seismic noise remains an important issue for Virgo. Vibrations produced by the detector infrastructure (such as air conditioning units, water chillers/heaters, pumps) are found to affect Virgo's sensitivity, with the main coupling mechanisms being through beam jitter and scattered light processes. The Advanced Virgo (AdV) design seeks to reduce ITF couplings to environmental noise by having most vibration-sensitive components suspended and in-vacuum, as well as muffle and relocate loud machines. During the months of June and July 2010, a Guralp-3TD seismometer was stationed at various locations around the Virgo site hosting major infrastructure machines. Seismic data were examined using spectral and coherence analysis with seismic probes close to the detector. The primary aim of this study was to identify noisy machines which seismically affect the ITF environment and thus require mitigation attention. Analyzed machines are located at various distances from the experimental halls, ranging from 10m to 100m. An attempt is made to measure the attenuation of emitted noise at the ITF and correlate it to the distance from the source and to seismic attenuation models in soil.
TL;DR: In this article, an omission in the Collaboration author list of S. S. Dwyer has been corrected. But the list is incorrect in the printed version of the journal.
Abstract: This paper was published online on 5 May 2010 with an omission in the Collaboration author list. S. Dwyer has been added as of 12 April 2012. The Collaboration author list is incorrect in the printed version of the journal
01 Jun 2012
TL;DR: The framework into which monitoring tools to perform online and offline noise analysis in areas such as transient signal detection, line identification algorithms and coherence are integrated - the Noise Monitor Application Programming Interface (NMAPI) is described.
Abstract: The understanding of noise in interferometric gravitational wave detectors is fundamental in terms of both enabling prompt reactions in the mitigation of noise disturbances and in the establishment of appropriate data-cleaning strategies. Monitoring tools to perform online and offline noise analysis in areas such as transient signal detection, line identification algorithms and coherence are used to characterise the Virgo detector noise. In this paper, we describe the framework into which these tools are integrated - the Noise Monitor Application Programming Interface (NMAPI) - and provide examples of its application.
21 Jun 2012
TL;DR: In this paper, the status of the commissioning of the Virgo interferometer is discussed, where the mirrors of the Fabry-Perot cavities are replaced by new ones with an higher reflectivity, which should increase by three times the finesse of the cavities.
Abstract: Long baseline optical interferometry is a promising technique for the detection of gravitational waves [1], [2], [3], [4]. The French-Italian detector Virgo is a Michelson interferometer with 3 km arms, equipped with high storage time Fabry-Perot cavities. In this kind of detectors, the passage of gravitational waves would be sensed as a differential length variation of the arms. After the end of the second Virgo Science Run, lasting from July 2009 to the beginning of January 2010, some important upgrades have been carried out; in particular, the mirrors of the Fabry-Perot cavities, which act as test masses of the detector, have been replaced by new ones with an higher reflectivity, which should increase by three times the finesse of the cavities; moreover the mirrors are now suspended by silica fibers in a monolithic assembly expected to significantly lower the thermal noise. Finally, the digital signal processing electronics and the global control system have been largely improved. We will present the status of the commissioning of the Virgo interferometer.
TL;DR: In this paper, an omission in the Collaboration author list of S. S. Dwyer has been corrected. But the list is incorrect in the printed version of the journal.
Abstract: This paper was published online on 5 November 2010 with an omission in the Collaboration author list. S. Dwyer has been added as of 12 April 2012. The Collaboration author list is incorrect in the printed version of the journal
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TL;DR: In this article, a rigorous analysis of experimental data is reported, the results are discussed and compared with theoretical predictions based on Lifshitz theory of dispersion forces, and the BCS formula for the optical conductivity of superconductors.
Abstract: The ALADIN experiment aims at observing how the critical magnetic field of a superconducting Aluminum film is modified, when it constitutes one of the reflecting surfaces of a Casimir cavity. If successful, such an observation would reveal the influence of vacuum energy on the superconducting phase transition. In this paper a rigorous analysis of experimental data is reported, the results are discussed and compared with theoretical predictions based on Lifshitz theory of dispersion forces, and the BCS formula for the optical conductivity of superconductors. The main novelty with respect to a previous data analysis by some of the authors, is the use of a cross-correlation method which is more rigorous and leads to better estimates.