On Black Hole Echoes [CL]

http://arxiv.org/abs/1912.05584


We consider gravitational wave echoes from black hole merger ringdowns which may arise from local Lorentz symmetry violations that modify graviton dispersion relations. If the corrections are sufficiently soft so they do not remove the horizon, the reflection of the infalling waves which trigger the echoes is very weak. As an example, we look at the dispersion relation corrected by roton-like operators depending only on spatial momenta, in Gullstrand-Painlev\’e coordinates. The near-horizon regions of a black hole do become reflective, but only very weakly. The resulting “bounces” of infalling waves can yield repetitive gravity wave emissions but their power is very small. This implies that to see any echoes from black holes we really need an egregious departure from either standard GR or effective field theory, or both.

Read this paper on arXiv…

G. D’Amico and N. Kaloper
Fri, 13 Dec 19
59/75

Comments: 10 pages, 3 figures