MOCCA-SURVEY Database I: Coalescing Binary Black Holes Originating From Globular Clusters

TL;DR

This paper uses a large set of simulated globular cluster models to estimate the properties and merger rates of binary black holes originating from these clusters, providing valuable insights into their astrophysical significance.

Contribution

It introduces a comprehensive analysis of coalescing binary black holes from globular clusters using the MOCCA simulation database, offering new statistical estimates of merger rates.

Findings

Estimated local merger rate density of at least 5.4 Gpc^{-3} yr^{-1}

Large statistical sample of BBHs with stellar and massive stellar BH components

Analysis of BBHs that escape or merge within clusters within a Hubble time

Abstract

In this first of a series of papers, we utilize results for around two thousand star cluster models simulated using the MOCCA code for star cluster evolution (Survey Database I) to determine the astrophysical properties and local merger rate densities for coalescing binary black holes (BBHs) originating from globular clusters (GCs). We extracted information for all coalescing BBHs that escape the cluster models and subsequently merge within a Hubble time along with BBHs that are retained in our GC models and merge inside the cluster via gravitational wave (GW) emission. By obtaining results from a substantial number of realistic star cluster models that cover different initial parameters, we have an extremely large statistical sample of BBHs with stellar mass and massive stellar BH ($\lesssim 100M_{\odot}$) components that merge within a Hubble time. Using this data, we estimate local merger rate densities for these BBHs originating from GCs to be at least 5.4 ${\rm Gpc}^{-3}\,{\rm yr}^{-1}$