-
the LIGO Scientific Collaboration,
the Virgo Collaboration,
J. Aasi,
J. Abadie,
B. P. Abbott,
R. Abbott,
T. D. Abbott,
M. Abernathy,
T. Accadia,
F. Acernese, [......],
M. Yvert,
A. Zadrożny,
M. Zanolin,
J. -P. Zendri,
F. Zhang,
L. Zhang,
C. Zhao,
N. Zotov,
M. E. Zucker,
J. Zweizig
[show abstract]
[hide abstract]
ABSTRACT: Compact binary systems with neutron stars or black holes are one of the most
promising sources for ground-based gravitational wave detectors. Gravitational
radiation encodes rich information about source physics; thus parameter
estimation and model selection are crucial analysis steps for any detection
candidate events. Detailed models of the anticipated waveforms enable inference
on several parameters, such as component masses, spins, sky location and
distance that are essential for new astrophysical studies of these sources.
However, accurate measurements of these parameters and discrimination of models
describing the underlying physics are complicated by artifacts in the data,
uncertainties in the waveform models and in the calibration of the detectors.
Here we report such measurements on a selection of simulated signals added
either in hardware or software to the data collected by the two LIGO
instruments and the Virgo detector during their most recent joint science run,
including a "blind injection" where the signal was not initially revealed to
the collaboration. We exemplify the ability to extract information about the
source physics on signals that cover the neutron star and black hole parameter
space over the individual mass range 1 Msun - 25 Msun and the full range of
spin parameters. The cases reported in this study provide a snap-shot of the
status of parameter estimation in preparation for the operation of advanced
detectors.
04/2013;
-
The LIGO Scientific Collaboration,
the Virgo Collaboration,
J. Aasi,
J. Abadie,
B. P. Abbott,
R. Abbott,
T. D. Abbott,
M. Abernathy,
T. Accadia,
F. Acernese, [......],
M. Yvert,
A. Zadrozny,
M. Zanolin,
J. -P. Zendri,
F. Zhang,
L. Zhang,
C. Zhao,
N. Zotov,
M. E. Zucker,
J. Zweizig
[show abstract]
[hide abstract]
ABSTRACT: We report a search for gravitational waves from the inspiral, merger and
ringdown of binary black holes (BBH) with total mass between 25 and 100 solar
masses, in data taken at the LIGO and Virgo observatories between July 7, 2009
and October 20, 2010. The maximum sensitive distance of the detectors over this
period for a (20,20) Msun coalescence was 300 Mpc. No gravitational wave
signals were found. We thus report upper limits on the astrophysical
coalescence rates of BBH as a function of the component masses for non-spinning
components, and also evaluate the dependence of the search sensitivity on
component spins aligned with the orbital angular momentum. We find an upper
limit at 90% confidence on the coalescence rate of BBH with non-spinning
components of mass between 19 and 28 Msun of 3.3 \times 10^-7 mergers /Mpc^3
/yr.
09/2012;
-
J. Aasi,
J. Abadie,
B. P. Abbott,
R. Abbott,
T. D. Abbott,
M. Abernathy,
T. Accadia,
F. Acernese,
C. Adams,
T. Adams, [......],
A. Zadrożny,
M. Zanolin,
J. -P. Zendri,
F. Zhang,
L. Zhang,
C. Zhao,
N. Zotov,
M. E. Zucker,
J. Zweizig,
D. P. Anderson
[show abstract]
[hide abstract]
ABSTRACT: This paper presents results of an all-sky searches for periodic gravitational
waves in the frequency range [50, 1190] Hz and with frequency derivative ranges
of [-2 x 10^-9, 1.1 x 10^-10] Hz/s for the fifth LIGO science run (S5). The
novelty of the search lies in the use of a non-coherent technique based on the
Hough-transform to combine the information from coherent searches on timescales
of about one day. Because these searches are very computationally intensive,
they have been deployed on the Einstein@Home distributed computing project
infrastructure. The search presented here is about a factor 3 more sensitive
than the previous Einstein@Home search in early S5 LIGO data. The
post-processing has left us with eight surviving candidates. We show that
deeper follow-up studies rule each of them out. Hence, since no statistically
significant gravitational wave signals have been detected, we report upper
limits on the intrinsic gravitational wave amplitude h0. For example, in the
0.5 Hz-wide band at 152.5 Hz, we can exclude the presence of signals with h0
greater than 7.6 x 10^-25 with a 90% confidence level.
07/2012;
-
The ANTARES Collaboration,
the LIGO Scientific Collaboration,
the Virgo Collaboration,
S. Adrián-Martínez,
I. Al Samarai,
A. Albert,
M. André,
M. Anghinolfi,
G. Anton,
S. Anvar, [......],
M. Yvert,
A. Zadroźny,
M. Zanolin,
J. -P. Zendri,
F. Zhang,
L. Zhang,
C. Zhao,
N. Zotov,
M. E. Zucker,
J. Zweizig
[show abstract]
[hide abstract]
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.
05/2012;
-
The LIGO Scientific Collaboration,
Virgo Collaboration,
J. Abadie,
B. P. Abbott,
R. Abbott,
T. D. Abbott,
M. Abernathy,
T. Accadia,
F. Acernese,
C. Adams, [......],
N. Zotov,
M. E. Zucker,
J. Zweizig,
M. S. Briggs,
V. Connaughton,
K. C. Hurley,
P. A. Jenke,
A. von Kienlin,
A. Rau,
X. -L. Zhang
[show abstract]
[hide abstract]
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.
05/2012;
-
P. A. Evans,
J. K. Fridriksson,
N. Gehrels,
J. Homan,
J. P. Osborne,
M. Siegel,
A. Beardmore,
P. Handbauer,
J. Gelbord,
J. A. Kennea, [......],
M. Yvert,
A. Zadrozny,
M. Zanolin,
J. -P. Zendri,
F. Zhang,
L. Zhang,
C. Zhao,
N. Zotov,
M. E. Zucker,
J. Zweizig
[show abstract]
[hide abstract]
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.
05/2012;
-
[show abstract]
[hide abstract]
ABSTRACT: We present an experimental analysis of force noise caused by stray electrostatic fields acting on a charged test mass inside a conducting enclosure, a key problem for precise gravitational experiments. Measurement of the average field that couples to the test mass charge, and its fluctuations, is performed with two independent torsion pendulum techniques, including direct measurement of the forces caused by a change in electrostatic charge. We analyze the problem with an improved electrostatic model that, coupled with the experimental data, also indicates how to correctly measure and null the stray field that interacts with the test mass charge. Our measurements allow a conservative upper limit on acceleration noise, of 2 (fm/s2)/Hz(1/2) for frequencies above 0.1 mHz, for the interaction between stray fields and charge in the LISA gravitational wave mission.
Physical Review Letters 05/2012; 108(18):181101. · 7.37 Impact Factor
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[show abstract]
[hide abstract]
ABSTRACT: Under micro-gravity conditions, typical of the space environment, adhesion forces may play a relevant role in the manipulation
of objects, especially when they must be released into free-fall under controlled residual velocity conditions. When only
contact forces may be applied to the body that must be released to free-fall, no solution different from inertia is available
to detach it from the manipulating device. If the manipulator is retracted from the body quickly enough, any adhesive bond
existing between them is brought to failure, being loaded by the inertia force. The body acquires a residual momentum equal
to the impulse developed by the adhesion force upon its failure. An experimental technique has been developed to characterize
the impulse that adhesive junctions between two metallic rough surfaces develop upon dynamic failure, as part of the qualification
of a system (the Caging Mechanism) designed for this specific function in the frame of the LISA Pathfinder space mission by
the European Space Agency (ESA). This paper reports on the recent results obtained through the experimental campaigns performed
in the LISA Pathfinder ground testing activities of the Caging Mechanism.
KeywordsDynamic failure of adhesion-Impulse measurement-Momentum transfer
Experimental Mechanics 04/2012; 50(8):1213-1223. · 1.52 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: The present paper is aimed at investigating the dynamics of release of objects in free-falling conditions, which constitutes
a typical phase of some space applications. In the presence of surface interaction forces, a quick separation of the released
body from the constraining one will result in a momentum transfer, provided that the inertial forces exceed the maximum attractive
force. The release conditions as well as the related parameters affecting the momentum acquired by the released body through
the adhesion rupture play a fundamental role. An experimental technique aimed at measuring the momentum transfer has been
developed. The basic concept of the measuring apparatus is to suspend both bodies from two pendulums. A position sensor detects
the weakly damped oscillation of one object due to the momentum transferred upon pulling the other one away. Particular attention
has been placed on the capability to accurately reproduce the stress status on the adhesive contact patch between the two
bodies, on the noise sources affecting the measurement, and on the performances of a noise optimal-filtering technique. This
paper presents measurements of momentum transfer between adhered surfaces upon quick separation.
Experimental Mechanics 04/2012; 48(6):777-787. · 1.52 Impact Factor
-
LIGO Scientific Collaboration,
Virgo Collaboration,
J. Abadie,
B. P. Abbott,
R. Abbott,
T. D. Abbott,
M. Abernathy,
T. Accadia,
F. Acernese,
C. Adams, [......],
R. Fender,
N. Gehrels,
A. Klotz,
E. O. Ofek,
M. Smith,
M. Sokolowski,
B. W. Stappers,
I. Steele,
J. Swinbank,
R. A. M. J. Wijeres
[show abstract]
[hide abstract]
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 ~50% or better probability with a few
pointings of wide-field telescopes.
Astronomy and Astrophysics 03/2012; 539:124. · 4.59 Impact Factor
-
LIGO Scientific Collaboration,
Virgo Collaboration,
J. Abadie,
B. P. Abbott,
R. Abbott,
T. D. Abbott,
M. Abernathy,
T. Accadia,
F. Acernese,
C. Adams, [......],
R. Fender,
N. Gehrels,
A. Klotz,
E. O. Ofek,
M. Smith,
M. Sokolowski,
B. W. Stappers,
I. Steele,
J. Swinbank,
R. A. M. J. Wijeres
[show abstract]
[hide abstract]
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 ~50% or better probability with a few
pointings of wide-field telescopes.
Astronomy and Astrophysics 03/2012; 539:124. · 4.59 Impact Factor
-
T Accadia,
F Acernese,
M Alshourbagy,
P Amico,
F Antonucci,
S Aoudia,
N Arnaud,
C Arnault,
K G Arun,
P Astone, [......],
J -Y Vinet,
S Vilalte, S Vitale,
H Vocca,
R L Ward,
M Was,
K Yamamoto,
M Yvert,
J -P Zendri,
Z Zhang
[show abstract]
[hide abstract]
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.
Journal of Instrumentation 03/2012; 7(03):P03012. · 1.87 Impact Factor
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J. Aasi,
J. Abadie,
B. P. Abbott,
R. Abbott,
T. D. Abbott,
M. Abernathy,
T. Accadia,
F. Acernese,
C. Adams,
T. Adams, [......],
M. Yvert,
A. Zadrożny,
M. Zanolin,
J. -P. Zendri,
F. Zhang,
L. Zhang,
C. Zhao,
N. Zotov,
M. E. Zucker,
J. Zweizig
[show abstract]
[hide abstract]
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.
03/2012;
-
the LIGO Scientific Collaboration,
the Virgo Collaboration,
J. Abadie,
B. P. Abbott,
R. Abbott,
T. D. Abbott,
M. Abernathy,
T. Accadia,
F. Acernese,
C. Adams, [......],
A. Zadrozny,
M. Zanolin,
J. -P. Zendri,
F. Zhang,
L. Zhang,
W. Zhang,
C. Zhao,
N. Zotov,
M. E. Zucker,
J. Zweizig
[show abstract]
[hide abstract]
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 < 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 5
10^-22 Hz^-1/2 to 1 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.
02/2012;
-
the LIGO Scientific Collaboration,
the Virgo Collaboration,
J. Abadie,
B. P. Abbott,
R. Abbott,
T. D. Abbott,
M. Abernathy,
T. Accadia,
F. Acernese,
C. Adams, [......],
A. Zadrozny,
M. Zanolin,
J. -P. Zendri,
F. Zhang,
L. Zhang,
W. Zhang,
C. Zhao,
N. Zotov,
M. E. Zucker,
J. Zweizig
[show abstract]
[hide abstract]
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.
01/2012;
-
J. Abadie,
B. P. Abbott,
R. Abbott,
T. D. Abbott,
M. Abernathy,
T. Accadia,
F. Acernese,
C. Adams,
R. Adhikari,
C. Affeldt, [......],
A. Zadroźny,
M. Zanolin,
J. -P. Zendri,
F. Zhang,
L. Zhang,
W. Zhang,
C. Zhao,
N. Zotov,
M. E. Zucker,
J. Zweizig
[show abstract]
[hide abstract]
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 $\Omega_{\rm GW}(f) = \Omega_3 (f/900
\mathrm{Hz})^3$, of $\Omega_3 < 0.33$, assuming a value of the Hubble parameter
of $h_{100}=0.72$. These new limits are a factor of seven better than the
previous best in this frequency band.
12/2011;
-
[show abstract]
[hide abstract]
ABSTRACT: In the frame of many scientific space missions, a massive free-falling object is required to mark a geodesic trajectory, i.e., to follow inside a spacecraft an orbit that is determined only by the planetary gravity field. The achievement of high-purity geodesic trajectories sets tight design constraints on the reference sensor that hosts and controls the reference body. Among these, a mechanism may be required to cage the reference body during the spacecraft launch and to inject it into the geodesic trajectory once on-orbit. The separation of the body from the injection mechanism must be realized against the action of adhesion forces, and in the worst case this is performed dynamically, relying on the body's inertia through a quick retraction of the holding finger(s). Unfortunately, this manoeuvre may not avoid transferring some momentum to the body, which may affect or even jeopardize the subsequent spacecraft control if the residual velocity is too large. The transferred momentum measurement facility (TMMF) was developed to reproduce representative conditions of the in-flight dynamic injection and to measure the transferred momentum to the released test mass. In this paper, we describe the design and development of the TMMF together with the achieved measurement performance.
The Review of scientific instruments 12/2011; 82(12):125107. · 1.52 Impact Factor
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the LIGO Scientific Collaboration,
the Virgo Collaboration,
J. Abadie,
B. P. Abbott,
R. Abbott,
T. D. Abbott,
M. Abernathy,
T. Accadia,
F. Acernese,
C. Adams, [......],
M. Zanolin,
J. -P. Zendri,
F. Zhang,
L. Zhang,
W. Zhang,
Z. Zhang,
C. Zhao,
N. Zotov,
M. E. Zucker,
J. Zweizig
[show abstract]
[hide abstract]
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 25
solar masses; 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.
11/2011;
-
[show abstract]
[hide abstract]
ABSTRACT: The LISA Pathfinder data analysis team has been developing in the last years
the infrastructure and methods required to run the mission during flight
operations. These are gathered in the LTPDA toolbox, an object oriented MATLAB
toolbox that allows all the data analysis functionalities for the mission,
while storing the history of all operations performed to the data, thus easing
traceability and reproducibility of the analysis. The parameter estimation
methods in the toolbox have been applied recently to data sets generated with
the OSE (Off-line Simulations Environment), a detailed LISA Pathfinder
non-linear simulator that will serve as a reference simulator during mission
operations. These operational exercises aim at testing the on-orbit experiments
in a realistic environment in terms of software and time constraints. These
simulations, so called operational exercises, are the last verification step
before translating these experiments into tele-command sequences for the
spacecraft, producing therefore very relevant datasets to test our data
analysis methods. In this contribution we report the results obtained with
three different parameter estimation methods during one of these operational
exercises.
11/2011;
-
[show abstract]
[hide abstract]
ABSTRACT: Coalescences of binary neutron stars and/or black holes are amongst the most
likely gravitational-wave signals to be observed in ground based
interferometric detectors. Apart from the astrophysical importance of their
detection, they will also provide us with our very first empirical access to
the genuinely strong-field dynamics of General Relativity (GR). We present a
new framework based on Bayesian model selection aimed at detecting deviations
from GR, subject to the constraints of the Advanced Virgo and LIGO detectors.
The method tests the consistency of coefficients appearing in the waveform with
the predictions made by GR, without relying on any specific alternative theory
of gravity. The framework is suitable for low signal-to-noise ratio events
through the construction of multiple subtests, most of which involve only a
limited number of coefficients. It also naturally allows for the combination of
information from multiple sources to increase one's confidence in GR or a
violation thereof. We expect it to be capable of finding a wide range of
possible deviations from GR, including ones which in principle cannot be
accommodated by the model waveforms, on condition that the induced change in
phase at frequencies where the detectors are the most sensitive is comparable
to the effect of a few percent change in one or more of the low-order
post-Newtonian phase coefficients. In principle the framework can be used with
any GR waveform approximant, with arbitrary parameterized deformations, to
serve as model waveforms. In order to illustrate the workings of the method, we
perform a range of numerical experiments in which simulated gravitational waves
modeled in the restricted post-Newtonian, stationary phase approximation are
added to Gaussian and stationary noise that follows the expected Advanced
LIGO/Virgo noise curves.
10/2011;
