https://doi.org/10.1140/epjp/s13360-021-01227-z
Review
Lessons from black hole quasinormal modes in modified gravity
1
Institute of Physics, Academia Sinica, 11529, Taipei, Taiwan
2
Department of Physics, University of the Basque Country UPV/EHU, 48080, Bilbao, Spain
3
IKERBASQUE, Basque Foundation for Science, 48011, Bilbao, Spain
4
Department of Physics and Center for Theoretical Sciences, National Taiwan University, 10617, Taipei, Taiwan
5
LeCosPA, National Taiwan University, 10617, Taipei, Taiwan
6
Kavli Institute for Particle Astrophysics and Cosmology, SLAC National Accelerator Laboratory, Stanford University, 94305, Stanford, CA, USA
Received:
29
January
2021
Accepted:
11
February
2021
Published online:
23
February
2021
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 paper, we 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 direct alterations of QNM spectra as compared with those in GR, (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. The prospects and possible challenges associated with future observations will be also discussed.
© The Author(s), under exclusive licence to Società Italiana di Fisica and Springer-Verlag GmbH Germany, part of Springer Nature 2021
