Impact of LIGO-Virgo black hole binaries on gravitational wave background searches

TL;DR

This paper assesses how black hole binaries detected by LIGO-Virgo affect future searches for primordial gravitational wave backgrounds, showing that astrophysical foregrounds significantly limit sensitivity.

Contribution

It provides an estimation of the astrophysical foreground from black hole binaries and evaluates its impact on future gravitational wave background searches.

Findings

Future experiments' sensitivity will be severely limited by astrophysical foregrounds.

Subtracting resolvable binaries reduces foreground but does not eliminate impact.

Even optimistic assumptions do not fully mitigate the foreground's effect.

Abstract

We study the impact of the black hole binary population currently probed by LIGO-Virgo on future searches for the primordial gravitational wave background. We estimate the foreground generated by the binaries using the observed event rate and a simple modeling of the black hole population. We subtract individually resolvable binaries from the foreground and utilize Fisher analysis to derive sensitivity curves for power-law signals including these astrophysical foregrounds. Even with optimistic assumptions, we find that the reach of future experiments will be severely reduced.