Black Hole Spectroscopy Tools for Waveform Modelling

In the quickly advancing field of black hole spectroscopy, many tools that improve our understanding have become available. In this talk, I briefly overview two recent public tools for extracting the quasinormal mode amplitudes. The first tool consists of both Python- and Mathematica-based codes, qnmfits and KerrRingdown, that take a generic waveform and extract these amplitudes through linear least-squares fitting and equivalent methods. The second tool predicts the remnant parameters of a binary black hole and the quasinormal amplitudes for areas of parameter space where we lack simulations. This surrogate model, NRSurr3dq8_RD, is trained on CCE waveforms in the superrest frame of the remnant black hole. With these tools at hand, one can easily build an analytical ringdown waveform.