Host galaxy identification for binary black hole mergers with long baseline gravitational wave detectors

TL;DR

Future long-baseline gravitational wave detectors could significantly increase detection rates and localization precision of binary black hole mergers, enabling detailed host galaxy identification and advancing astrophysical and cosmological research.

Contribution

This paper evaluates the science benefits of 8 km arm length gravitational wave detectors, highlighting their potential to greatly improve detection rates and source localization compared to current detectors.

Findings

Detection rate could increase to 10^3–10^5 per year.

Approximately 10 events within 0.4 Gpc could be localized to 0.1 deg^2.

Precise localization enables host galaxy identification and cosmological studies.

Abstract

The detection of three black hole binary coalescence events by Advanced LIGO allows the science benefits of future detectors to be evaluated. In this paper we report the science benefits of one or two 8km arm length detectors based on the doubling of key parameters in an advanced LIGO type detector, combined with realisable enhancements. It is shown that the total detection rate for sources similar to those already detected, would increase to $\sim$ 10$^{3}$--10$^{5}$ per year. Within 0.4Gpc we find that around 10 of these events would be localizable to within $\sim 10^{-1}$ deg$^2$. This is sufficient to make unique associations or to rule out a direct association with the brightest galaxies in optical surveys (at r-band magnitudes of 17 or above) or for deeper limits (down to r-band magnitudes of 20) yield statistically significant associations. The combination of angular resolution and event rate would benefit precision testing of formation models, cosmic evolution and cosmological studies.