2025/09/10 by Hai-Tian Wang, Wang, Hai-Tian · 1 citation
Earth and Planetary Sciences · Physics and Astronomy · #High-pressure geophysics and materials #Ionosphere and magnetosphere dynamics #Pulsars and Gravitational Waves Research
paper · pdf · doi:10.1103/114x-tj8m
The properties of a remnant black hole can be probed by analyzing the gravitational waves emitted during its ringdown phase. This signal provides a direct test of general relativity in the strong-field regime. In this study, we apply both a time-domain <a:math xmlns:a="http://www.w3.org/1998/Math/MathML"> <a:mrow> <a:mi mathvariant="script">F</a:mi> <a:mtext>-statistic</a:mtext> </a:mrow> </a:math> framework and full Bayesian time-domain sampling to the ringdown of GW231028153006. We report decisive evidence for multimode content, specifically identifying both the first overtone ( <c:math xmlns:c="http://www.w3.org/1998/Math/MathML"> <c:mrow> <c:mi>ℓ</c:mi> <c:mo>|</c:mo> <c:mi>m</c:mi> <c:mo>|</c:mo> <c:mi>n</c:mi> <c:mo>=</c:mo> <c:mn>221</c:mn> </c:mrow> </c:math> ) and the higher order ( <d:math xmlns:d="http://www.w3.org/1998/Math/MathML"> <d:mrow> <d:mi>ℓ</d:mi> <d:mo>|</d:mo> <d:mi>m</d:mi> <d:mo>|</d:mo> <d:mi>n</d:mi> <d:mo>=</d:mo> <d:mn>210</d:mn> </d:mrow> </d:math> ). The detection of the 221 mode is statistically significant, achieving a Bayes factor of <e:math xmlns:e="http://www.w3.org/1998/Math/MathML"> <e:mrow> <e:mo>∼</e:mo> <e:mn>189.2</e:mn> </e:mrow> </e:math> and an amplitude exclusion from zero at <f:math xmlns:f="http://www.w3.org/1998/Math/MathML"> <f:mrow> <f:mo>></f:mo> <f:mn>7</f:mn> <f:mi>σ</f:mi> </f:mrow> </f:math> credibility for an analysis beginning at <g:math xmlns:g="http://www.w3.org/1998/Math/MathML"> <g:mrow> <g:mn>10</g:mn> <g:mi>M</g:mi> </g:mrow> </g:math> postpeak. These findings are rigorously validated against the numerical relativity injection SXS:BBH:1282, which confirms that such multimode features are physically expected for a remnant with the inferred high spin and mass ratio. The inclusion of the overtone mode allows for precise constraints on the remnant's properties, yielding a redshifted final mass of <h:math xmlns:h="http://www.w3.org/1998/Math/MathML"> <h:mrow> <h:mn>246</h:mn> <h:mo>.</h:mo> <h:msubsup> <h:mn>2</h:mn> <h:mrow> <h:mo>−</h:mo> <h:mn>22.4</h:mn> </h:mrow> <h:mrow> <h:mo>+</h:mo> <h:mn>22.3</h:mn> </h:mrow> </h:msubsup> <h:msub> <h:mi>M</h:mi> <h:mo>⊙</h:mo> </h:msub> </h:mrow> </h:math> and a final spin of <i:math xmlns:i="http://www.w3.org/1998/Math/MathML"> <i:mrow> <i:mn>0</i:mn> <i:mo>.</i:mo> <i:msubsup> <i:mn>81</i:mn> <i:mrow> <i:mo>−</i:mo> <i:mn>0.10</i:mn> </i:mrow> <i:mrow> <i:mo>+</i:mo> <i:mn>0.07</i:mn> </i:mrow> </i:msubsup> </i:mrow> </i:math> (at <j:math xmlns:j="http://www.w3.org/1998/Math/MathML"> <j:mrow> <j:mn>90</j:mn> <j:mo>%</j:mo> </j:mrow> </j:math> credibility), consistent with full inspiral-merger-ringdown predictions. A test of the no-hair theorem, enabled by this robust multimode detection, shows consistency with general relativity.