Accessibility of the Gravitational-Wave Background due to Binary Coalescences to Second and Third Generation Gravitational-Wave Detectors

TL;DR

This paper evaluates how well current and future gravitational-wave detectors can observe the background noise from binary coalescences, highlighting detection prospects and challenges in isolating cosmological signals.

Contribution

It systematically analyzes the binary coalescence gravitational-wave background across parameter space and compares it to detector sensitivities, revealing detection likelihoods and the need for signal subtraction.

Findings

Second-generation detectors are likely to detect the binary coalescence GWB.

Third-generation detectors will probe most of the parameter space.

The binary coalescence GWB may mask cosmological backgrounds, requiring subtraction of signals.

Abstract

Compact binary coalescences, such as binary neutron stars or black holes, are among the most promising candidate sources for the current and future terrestrial gravitational-wave detectors. While such sources are best searched using matched template techniques and chirp template banks, integrating chirp signals from binaries over the entire Universe also leads to a gravitational-wave background (GWB). In this paper we systematically scan the parameter space for the binary coalescence GWB models, taking into account uncertainties in the star formation rate and in the delay time between the formation and coalescence of the binary, and we compare the computed GWB to the sensitivities of the second and third generation gravitational-wave detector networks. We find that second generation detectors are likely to detect the binary coalescence GWB, while the third generation detectors will probe most of the available parameter space. The binary coalescence GWB will, in fact, be a foreground for the third-generation detectors, potentially masking the GWB background due to cosmological sources. Accessing the cosmological GWB with third generation detectors will therefore require identification and subtraction of all inspiral signals from all binaries in the detectors' frequency band.