Black hole spectroscopy: from theory to experiment

TL;DR

This paper reviews the theoretical predictions and experimental prospects of black hole ringdown signals, emphasizing their importance for testing general relativity, exploring new physics, and advancing gravitational-wave astronomy.

Contribution

It provides a comprehensive overview of black hole quasinormal modes, their modeling, and the current status of observational data analysis in gravitational-wave astronomy.

Findings

Summary of black hole quasinormal mode theory in GR and modified gravity

Review of current LIGO-Virgo-KAGRA ringdown observations

Discussion of future prospects with LISA and next-generation detectors

Abstract

The "ringdown" radiation emitted by oscillating black holes has great scientific potential. By carefully predicting the frequencies and amplitudes of black hole quasinormal modes and comparing them with gravitational-wave data from compact binary mergers we can advance our understanding of the two-body problem in general relativity, verify the predictions of the theory in the regime of strong and dynamical gravitational fields, and search for physics beyond the Standard Model or new gravitational degrees of freedom. We summarize the state of the art in our understanding of black hole quasinormal modes in general relativity and modified gravity, their excitation, and the modeling of ringdown waveforms. We also review the status of LIGO-Virgo-KAGRA ringdown observations, data analysis techniques, and the bright prospects of the field in the era of LISA and next-generation ground-based gravitational-wave detectors.