Confronting primordial black holes with LIGO-Virgo-KAGRA and the Einstein Telescope

TL;DR

This paper investigates whether primordial black holes could explain some of the gravitational wave events detected by LIGO-Virgo-KAGRA, using Bayesian analysis to constrain models and forecast detection prospects with future detectors.

Contribution

It provides the first Bayesian constraints on PBH contributions to GW events and predicts how future detectors can distinguish PBHs from astrophysical black holes.

Findings

Stellar-mass PBHs cannot dominate cold dark matter.

Approximately 25% of GWTC-3 events may originate from PBH binaries.

Future detectors like the Einstein Telescope can differentiate PBHs from ABHs based on redshift evolution.

Abstract

The detection of gravitational waves (GWs) from binary black hole (BBH) coalescences by the LIGO-Virgo-KAGRA (LVK) Collaboration has raised fundamental questions about the genesis of these events. In this chapter, we explore the possibility that PBHs, proposed candidates for dark matter, may serve as the progenitors of the BBHs observed by LVK. Employing a Bayesian analysis, we constrain the PBH model using the LVK third GW Transient Catalog (GWTC-3), revealing that stellar-mass PBHs cannot dominate cold dark matter. Considering a mixed population of astrophysical black holes (ABHs) and PBHs, we determine that approximately $1/4$ of the detectable events in the GWTC-3 can be attributed to PBH binaries. We also forecast detectable event rate distributions for PBH and ABH binaries by the third-generation ground-based GW detectors, such as the Einstein Telescope, offering a potential avenue to distinguish PBHs from ABHs based on their distinct redshift evolutions.