Estimating parameters of coalescing compact binaries with proposed advanced detector networks

TL;DR

This paper evaluates how adding a fourth gravitational-wave detector site improves the accuracy of source localization and parameter estimation for coalescing binary systems, aiding electromagnetic follow-up efforts.

Contribution

It provides a Bayesian analysis of proposed detector networks, demonstrating the benefits of additional sites in breaking parameter degeneracies and improving sky localization.

Findings

Sky localization improves by a factor of 3-4 with an Australian site.

Indian site improves localization by a factor of 2.5-3.5.

Additional detectors modestly enhance distance and inclination estimates.

Abstract

The advanced versions of the LIGO and Virgo ground-based gravitational-wave detectors are expected to operate from three sites: Hanford, Livingston, and Cascina. Recent proposals have been made to place a fourth site in Australia or India; and there is the possibility of using the Large Cryogenic Gravitational Wave Telescope in Japan to further extend the network. Using Bayesian parameter-estimation analyses of simulated gravitational-wave signals from a range of coalescing-binary locations and orientations at fixed distance or signal-to-noise ratio, we study the improvement in parameter estimation for the proposed networks. We find that a fourth detector site can break degeneracies in several parameters; in particular, the localization of the source on the sky is improved by a factor of ~ 3--4 for an Australian site, or ~ 2.5--3.5 for an Indian site, with more modest improvements in distance and binary inclination estimates. This enhanced ability to localize sources on the sky will be crucial in any search for electromagnetic counterparts to detected gravitational-wave signals.