# Nonlinear Effects in the Black Hole Ringdown

#### Nonlinear Effects in the Black Hole Ringdown

- Event time: 1:00pm until 3:00pm
- Event date: 15th May 2024
- Speaker: Pablo Bosch (University of Amsterdam)
- Location: Room 4325B, James Clerk Maxwell Building (JCMB) James Clerk Maxwell Building Peter Guthrie Tait Road Edinburgh EH9 3FD GB

### Event details

Title: Nonlinear Effects in the Black Hole Ringdown

Abstract: Gravitational-wave observations of black hole ringdowns are commonly used to characterize binary merger remnants and to test general relativity. These analyses assume linear black hole perturbation theory, in particular that the ringdown can be described in terms of quasinormal modes even for times approaching the merger. Here we investigate a nonlinear effect during the ringdown, namely how a mode excited at early times can excite additional modes as it is absorbed by the black hole. Using nonlinear simulations, we study the ringdown of a spherically-symmetric scalar field around an asymptotically anti-de Sitter black hole, and we find that this "absorption-induced mode excitation" (AIME) is the dominant nonlinear effect. I will show our current progress for looking for these nonlinearities in current waveform models and the need to provide flexible nonlinear models.

### About Particle Physics Theory seminars

The Particle Physics Theory seminar is a weekly series of talks reflecting the diverse interests of the group. Topics include analytic and numerical calculations based on the Standard Model of elementary particle physics, theories exploring new physics, as well as more formal developments in gauge theories and gravity..