936 research outputs found
Seedless clustering in all-sky searches for gravitational-wave transients
The problem of searching for unmodeled gravitational-wave bursts can be
thought of as a pattern recognition problem: how to find statistically
significant clusters in spectrograms of strain power when the precise signal
morphology is unknown. In a previous publication, we showed how "seedless
clustering" can be used to dramatically improve the sensitivity of searches for
long-lived gravitational-wave transients. In order to manage the computational
costs, this initial analysis focused on externally triggered searches where the
source location and emission time are both known to some degree of precision.
In this paper, we show how the principle of seedless clustering can be extended
to facilitate computationally-feasible, all-sky searches where the direction
and emission time of the source are entirely unknown. We further demonstrate
that it is possible to achieve a considerable reduction in computation time by
using graphical processor units (GPUs), thereby facilitating more sensitive
searches.Comment: 9 pages, 2 figure
Gravitational-Wave Geodesy: A New Tool for Validating Detection of the Stochastic Gravitational-Wave Background
A valuable target for advanced gravitational-wave detectors is the stochastic
gravitational-wave background. The stochastic background imparts a weak
correlated signal into networks of gravitational-wave detectors, and so
standard searches for the gravitational-wave background rely on measuring
cross-correlations between pairs of widely-separated detectors. Stochastic
searches, however, can be affected by any other correlated effects which may
also be present, including correlated frequency combs and magnetic Schumann
resonances. As stochastic searches become sensitive to ever-weaker signals, it
is increasingly important to develop methods to separate a true astrophysical
signal from other spurious and/or terrestrial signals. Here, we describe a
novel method to achieve this goal -- gravitational-wave geodesy. Just as radio
geodesy allows for the localization of radio telescopes, so too can
observations of the gravitational-wave background be used to infer the
positions and orientations of gravitational-wave detectors. By demanding that a
true observation of the gravitational-wave background yield constraints
consistent with the baseline's known geometry, we demonstrate that we can
successfully validate true observations of the gravitational-wave background
while rejecting spurious signals due to correlated terrestrial effects.Comment: Minor typos correcte
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