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arXiv · 2507.20778

GW231123: Binary Black Hole Merger or Cosmic String?

Iuliu Cuceu·Marie Anne Bizouard·Nelson Christensen·Mairi Sakellariadou
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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.

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Iuliu Cuceu, Marie Anne Bizouard, Nelson Christensen, Mairi Sakellariadou. 2025-07-28. GW231123: Binary Black Hole Merger or Cosmic String?. https://doi.org/10.1103/zd8m-tzxd

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