Accuracy of ringdown models calibrated to numerical relativity simulations

This is the authors' abstract. We don't add key points for this paper.

The “ringdown” stage of gravitational-wave signals from binary black hole mergers, mainly consisting of a superposition of quasinormal modes emitted by the merger remnant, is a key tool to test fundamental physics and to probe black hole dynamics. However, ringdown models are known to be accurate only in the late-time, stationary regime. A key open problem in the field is to understand if these models are robust when extrapolated to earlier times, and if they can faithfully recover a larger portion of the signal. We address this question through a systematic time-domain calculation of the mismatch between nonprecessing, quasicircular ringdown models parametrized by the progenitor binary’s degrees of freedom and full numerical relativity inspiral-merger-ringdown waveforms from the simulating extreme spacetimes (SXS) simulation catalog. For the best-performing models, the mismatch is typically in the range <a:math xmlns:a="http://www.w3.org/1998/Math/MathML" display="inline"> <a:mo stretchy="false">[</a:mo> <a:msup> <a:mn>10</a:mn> <a:mrow> <a:mo>−</a:mo> <a:mn>6</a:mn> </a:mrow> </a:msup> <a:mo>,</a:mo> <a:msup> <a:mn>10</a:mn> <a:mrow> <a:mo>−</a:mo> <a:mn>4</a:mn> </a:mrow> </a:msup> <a:mo stretchy="false">]</a:mo> </a:math> for the <e:math xmlns:e="http://www.w3.org/1998/Math/MathML" display="inline"> <e:mo stretchy="false">(</e:mo> <e:mo>ℓ</e:mo> <e:mo>,</e:mo> <e:mo stretchy="false">|</e:mo> <e:mi>m</e:mi> <e:mo stretchy="false">|</e:mo> <e:mo stretchy="false">)</e:mo> <e:mo>=</e:mo> <e:mo stretchy="false">(</e:mo> <e:mn>2</e:mn> <e:mo>,</e:mo> <e:mn>2</e:mn> <e:mo stretchy="false">)</e:mo> </e:math> harmonic, and <m:math xmlns:m="http://www.w3.org/1998/Math/MathML" display="inline"> <m:mo stretchy="false">[</m:mo> <m:msup> <m:mn>10</m:mn> <m:mrow> <m:mo>−</m:mo> <m:mn>4</m:mn> </m:mrow> </m:msup> <m:mo>,</m:mo> <m:msup> <m:mn>10</m:mn> <m:mrow> <m:mo>−</m:mo> <m:mn>2</m:mn> </m:mrow> </m:msup> <m:mo stretchy="false">]</m:mo> </m:math> for higher-order modes. Our findings inform ongoing observational searches for quasinormal modes, and underscore the need for improved modeling of higher-order modes to meet the sensitivity requirements of future gravitational-wave detectors.