3 research outputs found
Search for a stochastic gravitational-wave signal in the second round of the Mock LISA Data Challenges
The analysis method currently proposed to search for isotropic stochastic
radiation of primordial or astrophysical origin with the Laser Interferometer
Space Antenna (LISA) relies on the combined use of two LISA channels, one of
which is insensitive to gravitational waves, such as the symmetrised Sagnac.
For this method to work, it is essential to know how the instrumental noise
power in the two channels are related to one another; however, no quantitative
estimates of this key information are available to date. The purpose of our
study is to assess the performance of the symmetrised Sagnac method for
different levels of prior information regarding the instrumental noise. We
develop a general approach in the framework of Bayesian inference and an
end-to-end analysis algorithm based on Markov Chain Monte Carlo methods to
compute the posterior probability density functions of the relevant model
parameters. We apply this method to data released as part of the second round
of the Mock LISA Data Challenges. For the selected (and somewhat idealised)
cases considered here, we find that a prior uncertainty of a factor ~2 in the
ratio between the power of the instrumental noise contributions in the two
channels allows for the detection of isotropic stochastic radiation. More
importantly, we provide a framework for more realistic studies of LISA's
performance and development of analysis techniques in the context of searches
for stochastic signals.Comment: 10 pages, 3 figures, GWDAW12 conference proceeding
The Mock LISA Data Challenges: from Challenge 1B to Challenge 3
The Mock LISA Data Challenges are a programme to demonstrate and encourage
the development of LISA data-analysis capabilities, tools and techniques. At
the time of this workshop, three rounds of challenges had been completed, and
the next was about to start. In this article we provide a critical analysis of
entries to the latest completed round, Challenge 1B. The entries confirm the
consolidation of a range of data-analysis techniques for Galactic and
massive--black-hole binaries, and they include the first convincing examples of
detection and parameter estimation of extreme--mass-ratio inspiral sources. In
this article we also introduce the next round, Challenge 3. Its data sets
feature more realistic waveform models (e.g., Galactic binaries may now chirp,
and massive--black-hole binaries may precess due to spin interactions), as well
as new source classes (bursts from cosmic strings, isotropic stochastic
backgrounds) and more complicated nonsymmetric instrument noise.Comment: 20 pages, 3 EPS figures. Proceedings of the 12th Gravitational Wave
Data Analysis Workshop, Cambridge MA, 13--16 December 2007. Typos correcte
The Mock LISA Data Challenges: from Challenge 3 to Challenge 4
The Mock LISA Data Challenges are a program to demonstrate LISA data-analysis
capabilities and to encourage their development. Each round of challenges
consists of one or more datasets containing simulated instrument noise and
gravitational waves from sources of undisclosed parameters. Participants
analyze the datasets and report best-fit solutions for the source parameters.
Here we present the results of the third challenge, issued in Apr 2008, which
demonstrated the positive recovery of signals from chirping Galactic binaries,
from spinning supermassive--black-hole binaries (with optimal SNRs between ~ 10
and 2000), from simultaneous extreme-mass-ratio inspirals (SNRs of 10-50), from
cosmic-string-cusp bursts (SNRs of 10-100), and from a relatively loud
isotropic background with Omega_gw(f) ~ 10^-11, slightly below the LISA
instrument noise.Comment: 12 pages, 2 figures, proceedings of the 8th Edoardo Amaldi Conference
on Gravitational Waves, New York, June 21-26, 200