Localizing compact binary inspirals on the sky using ground-based gravitational wave interferometers

TL;DR

This paper evaluates the sky localization capabilities of ground-based gravitational-wave detector networks for compact binary inspirals, demonstrating significant improvements with additional detectors and highlighting the potential for electromagnetic counterpart identification.

Contribution

It provides the first detailed analysis of sky localization accuracy for neutron star binaries using multiple ground-based GW detector networks with MCMC techniques.

Findings

LIGO-Virgo network localizes 50% of binaries within 50 sq.deg.

Adding LCGT and LIGO-Australia reduces localization to 12 sq.deg.

Enhanced detector networks improve sky localization, aiding EM counterpart searches.

Abstract

The inspirals and mergers of compact binaries are among the most promising events for ground-based gravitational-wave (GW) observatories. The detection of electromagnetic (EM) signals from these sources would provide complementary information to the GW signal. It is therefore important to determine the ability of gravitational-wave detectors to localize compact binaries on the sky, so that they can be matched to their EM counterparts. We use Markov Chain Monte Carlo techniques to study sky localization using networks of ground-based interferometers. Using a coherent-network analysis, we find that the Laser Interferometer Gravitational Wave Observatory (LIGO)-Virgo network can localize 50% of their ~8 sigma detected neutron star binaries to better than 50 sq.deg. with 95% confidence region. The addition of the Large Scale Cryogenic Gravitational Wave Telescope (LCGT) and LIGO-Australia improves this to 12 sq.deg.. Using a more conservative coincident detection threshold, we find that 50% of detected neutron star binaries are localized to 13 sq.deg. using the LIGO-Virgo network, and to 3 sq.deg. using the LIGO-Virgo-LCGT-LIGO-Australia network. Our findings suggest that the coordination of GW observatories and EM facilities offers great promise.