Speaker
Description
One important stage associated with the coalescence of two black holes is the ringdown phase, during which the remnant emits gravitational radiation described by black-hole perturbation theory. This gravitational radiation is characterized by quasinormal modes (QNMs) whose frequencies and damping times encode the properties of the spacetime and the underlying theory of gravity.
Notably, black hole QNMs may exhibit phenomena that can serve as a smoking gun to probe theories beyond General Relativity, where additional degrees of freedom arise. These phenomena include spectral instabilities, avoided crossings, and exceptional points. Motivated by this scenario, we develop a model-independent parameterization to obtain the excitation factors and the QNM frequency spectra of a general system of three coupled master equations on top of a Schwarzschild background. As an application, we consider a black hole in the Einstein-Maxwell-axion theory in the limit where quadratic contributions to the electric charge are neglected. We discuss our first results and the future steps.
| Topic | Modified theories of gravity, Gravitational waves |
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