Synergy between ground and space based gravitational wave detectors II: Localisation

TL;DR

Combining ground and space-based gravitational wave detectors significantly enhances the localization accuracy of black-hole binary sources, aiding in identifying their host galaxies and advancing gravitational wave astronomy.

Contribution

This work extends previous studies by including binary spin effects and analyzing different DECIGO orbits, demonstrating substantial localization improvements through combined measurements.

Findings

Order of magnitude improvement in localization accuracy.

Effective localization even with precursor DECIGO missions.

Enhanced prospects for identifying host galaxies.

Abstract

We study the advantage of combining measurements from future ground and space based gravitational wave detectors in estimating the parameters of a black-hole binary coalescence. This is an extension of our previous work (PTEP 053E01 (2016)) where we used pattern averaged waveform to study non-spinning binaries. In this work we study the localisation and binary plane orientation, including the (non-precessing) spin of binaries. We focus on the third generation terrestrial detector `Einstein telescope' and a proposed space based detector `Deci-Hertz Interferometer Gravitational wave Observatory' (DECIGO). We consider two possible orbits for DECIGO, a heliocentric orbit and a Sun-synchronous geocentric orbit. We demonstrate that one can obtain order of magnitude improvement in the localisation from the space-ground combined measurements, even with a precursor-DECIGO mission (B-DECIGO). This is especially important for the future of gravitational wave astronomy as improving the localisation accuracy further improves our chances of identifying the host galaxies of these binary systems.