Quasinormal mode content of binary black hole ringdowns
arXiv:2510.13954 · doi:10.1103/ptmd-rz1t
Abstract
We present a fully Bayesian, data-driven framework for identifying quasinormal modes in high-accuracy Cauchy-Characteristic Evolution (CCE) gravitational waveforms. Applying this to a public catalog, we identify QNM overtones, retrograde modes, and nonlinear modes up to cubic order in the ringdown. Multiple high-order overtones are found near the merger, confirming their physical significance for modeling the ringdown. The ringdown mode content is tabulated across a wide range of start times for all available simulations, providing a systematic reference for theoretical and observational studies. We also search for late-time power-law tails, which are, as expected, absent from the CCE waveforms.
Main text: 5 pages, 2 figures. Supplemental material: 2 pages