Time : 2022/04/14 (Thu.) 12:30
Title: Black Hole Quasinormal Modes in GR and Beyond

Abstract:
Quasinormal modes (QNMs) of perturbed black holes have recently gained
much interest because of their tight relations with the gravitational
wave signals emitted during the post-merger phase of a binary black hole
coalescence. One of the intriguing features of these modes is that they
respect the no-hair theorem, and hence, they can be used to test black
hole spacetimes and the underlying gravitational theory. In this talk, I
will exhibit three different aspects of how black hole QNMs could be
altered in theories beyond Einstein’s general relativity (GR). These
aspects are (i) the shift of QNM spectra with respect to their GR
counterparts, (ii) the violation of the geometric correspondence between
the high-frequency QNMs and the photon geodesics around the black hole,
and (iii) the breaking of the isospectrality between the axial and polar
gravitational perturbations. Several examples will be provided in each
individual case. A theory-agnostic approach to address this issue will
also be discussed.