GW231123: Binary black hole merger or cosmic string?

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 <a:math xmlns:a="http://www.w3.org/1998/Math/MathML" display="inline"> <a:msubsup> <a:mn>137</a:mn> <a:mrow> <a:mo>−</a:mo> <a:mn>17</a:mn> </a:mrow> <a:mrow> <a:mo>+</a:mo> <a:mn>22</a:mn> </a:mrow> </a:msubsup> <a:msub> <a:mi>M</a:mi> <a:mo stretchy="false">⊙</a:mo> </a:msub> </a:math> and <d:math xmlns:d="http://www.w3.org/1998/Math/MathML" display="inline"> <d:msubsup> <d:mn>103</d:mn> <d:mrow> <d:mo>−</d:mo> <d:mn>52</d:mn> </d:mrow> <d:mrow> <d:mo>+</d:mo> <d:mn>20</d:mn> </d:mrow> </d:msubsup> <d:msub> <d:mi>M</d:mi> <d:mo stretchy="false">⊙</d:mo> </d:msub> </d:math> (90% credible intervals). As seen by the two LIGO detectors, the signal has only <g:math xmlns:g="http://www.w3.org/1998/Math/MathML" display="inline"> <g:mo>∼</g:mo> <g:mn>5</g:mn> </g:math> cycles, between 30 and 80 Hz, over <i:math xmlns:i="http://www.w3.org/1998/Math/MathML" display="inline"> <i:mo>∼</i:mo> <i:mn>10</i:mn> <i:mtext> </i:mtext> <i:mtext> </i:mtext> <i:mi>ms</i:mi> </i:math> . 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 versus a cosmic string origin of the signal.