Perturbations of Kerr black holes during extreme mass-ratio inspiral gravitational wave events

Tommy Osburn (University College Dublin)

Time:

2PM Wednesday, 4 February 2026

Location:

Science East, E0.32

When a small compact object inspirals into a large black hole, gravitational waves are emitted with frequencies optimal for detection by the LISA gravitational wave space mission. Using general relativity to model these extreme mass-ratio systems involves black hole perturbation theory and self-force methods. This approach represents the spacetime curvature as an expansion beginning with the exact Kerr solution and then introducing perturbations that encode two-body interactions such as the emitted gravitational waves and the self-force acting on the small body. Because the Kerr solution only has two symmetries, it is not generally known how to apply the method of separation of variables to solve the perturbed field equations. This work involves calculating Kerr perturbations without imposing full separation of variables. By enforcing the limited number of symmetries available, the resulting field equations reduce to elliptic partial differential equations, which we solve numerically.