GW231123: Binary Black Hole Merger or Cosmic String?

TL;DR

This paper analyzes the gravitational-wave event GW231123 to determine whether it originated from a binary black hole merger or cosmic string phenomena, using Bayesian model comparison.

Contribution

The study applies Bayesian model comparison to distinguish between binary black hole and cosmic string origins of the GW231123 signal, providing evidence for a black hole merger.

Findings

Significant evidence supports a binary black hole merger origin.

The signal's characteristics are consistent with a black hole merger rather than cosmic strings.

Bayesian analysis effectively differentiates between the two models.

Abstract

The LIGO-Virgo-KAGRA Collaboration recently reported an exceptional gravitational-wave event, GW231123. This gravitational-wave signal was assumed to be generated from the merger of a binary black hole system, with source frame masses of $137^{+22}_{-17}~\textup{M}_\odot$ and $103^{+20}_{-52}~ \textup{M}_\odot$ (90\% credible intervals). As seen by the two LIGO detectors, the signal has only $\sim 5$ cycles, between 30 and 80 Hz, over $\sim 10$ ms. It is of critical importance to confirm the origin of this signal. Here we present the results of a Bayesian model comparison to test whether the gravitational-wave signal was actually generated by a binary black hole merger, or emitted from cusps or kinks on a cosmic string. We find significant evidence for a binary black hole merger origin of the signal.