Speaker
Description
Quasinormal modes (QNMs) are the characteristic complex frequencies that govern the ringdown phase of a black hole merger. While their frequencies depend only on the properties of the remnant, the strength with which different modes are excited is determined by the merger dynamics and remains poorly understood. Improving our knowledge of QNM excitation is key to maximizing the science return of black hole spectroscopy with current and future gravitational-wave detectors.
In this talk, I will examine the excitation of QNMs of Kerr black holes by a point particle plunging from the innermost stable circular orbit along a critical equatorial trajectory. Using the frequency-domain Sasaki–Nakamura formalism, we compute the excitation coefficients of individual modes and analyze how they vary with the final black hole spin.
I will present trends that identify which modes dominate the ringdown as the spin increases, clarifying the connection between plunge dynamics and QNM excitation. These results provide new insight into the relative mode amplitudes expected in realistic merger scenarios, with implications for parameter estimation and precision tests of general relativity.