Gravitational background from dynamical binaries and detectability with 2G detectors

TL;DR

This study models the gravitational wave background from binary black holes, considering young clusters, and predicts its detectability with second-generation detectors over several years.

Contribution

It introduces a comprehensive simulation including young cluster binaries and assesses their impact on the gravitational wave background detection prospects.

Findings

Binary black holes dominate the background.

Predicted energy density aligns with current observational limits.

Background features a bump from specific mass ranges.

Abstract

We study the impact of young clusters on the gravitational wave background from compact binary coalescence. We simulate a catalog of sources from population I/II isolated binary stars and stars born in young clusters, corresponding to one year of observations with second-generation (2G) detectors. Taking into account uncertainties on the fraction of dynamical binaries and star formation parameters, we find that the background is dominated by the population of binary black holes, and we obtain a value of $\Omega_{gw}(25 \rm{Hz}) = 1.2^{+1.38}_{-0.65} \times 10^{-9}$ for the energy density, in agreement with the actual upper limits derived from the latest observation run of LIGO--Virgo. We demonstrate that a large number of sources in a specific corrected mass range yields to a bump in the background. This background could be detected with 8 years of coincident data by a network of 2G detectors.