Matter effects in black hole quasi-normal modes

Black holes formed in the aftermath of compact binary mergers will emit quasi normal modes before settling down to their quiescent Kerr state. All the complex frequencies of the spectrum of (an infinite number of) modes at late times depend only on the mass and spin angular momentum of the final state. The amplitudes of the excited modes, however, depend on the properties of the progenitor binary. For example, in the case of binary black holes, the relative amplitudes of these quasinormal modes depend on the mass ratio and spins of the progenitor black holes. In this presentation, we will examine how the mode amplitudes depend on the properties of matter in the case of black holes that form promptly from neutron star mergers. More specifically, we explore which modes carry the signature of tidal deformability of progenitor neutron stars.