Black-hole ringdown as a probe of higher-curvature gravity theories

Understand

Detecting gravitational waves from coalescing compact binaries allows us to explore the dynamical, nonlinear regime of general relativity and constrain modifications to it.

• Some of the gravitational-wave events observed by the LIGO-Virgo Collaboration have sufficiently high signal-to-noise ratio in the merger, allowing us to probe the relaxation of the remnant black hole to its final, stationary state - the so-called black-hole ringdown, which is characterized by a set of quasinormal modes.
• Can we use the ringdown to constrain deviations from general relativity, as predicted by several of its contenders? Here, we address this question by using an inspiral-merger-ringdown waveform model in the effective-one-body formalism, augmented with a parametrization of the ringdown based on an expansion in the final black hole's spin.
• We give a prescription on how to include in this waveform model, the quasinormal mode frequencies calculated on a theory-by-theory basis.