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Free keywords:
Astrophysics, Instrumentation and Methods for Astrophysics, astro-ph.IM, Astrophysics, Solar and Stellar Astrophysics, astro-ph.SR
Abstract:
The problem of reconstructing the sky position of compact binary coalescences
detected via gravitational waves is a central one for future observations with
the ground-based network of gravitational-wave laser interferometers, such as
Advanced LIGO and Advanced Virgo. Different techniques for sky localisation
have been independently developed. They can be divided in two broad categories:
fully coherent Bayesian techniques, which are high-latency and aimed at
in-depth studies of all the parameters of a source, including sky position, and
"triangulation-based" techniques, which exploit the data products from the
search stage of the analysis to provide an almost real-time approximation of
the posterior probability density function of the sky location of a detection
candidate. These techniques have previously been applied to data collected
during the last science runs of gravitational-wave detectors operating in the
so-called initial configuration.
Here, we develop and analyse methods for assessing the self-consistency of
parameter estimation methods and carrying out fair comparisons between
different algorithms, addressing issues of efficiency and optimality. These
methods are general, and can be applied to parameter estimation problems other
than sky localisation. We apply these methods to two existing sky localisation
techniques representing the two above-mentioned categories, using a set of
simulated inspiral-only signals from compact binary systems with total mass
$\le 20\,M_\odot$ and non-spinning components. We compare the relative
advantages and costs of the two techniques and show that sky location
uncertainties are on average a factor $\approx 20$ smaller for fully coherent
techniques than for the specific variant of the "triangulation-based" technique
used during the last science runs, at the expense of a factor $\approx 1000$
longer processing time.
