Perturbed black holes in Einstein-dilaton-Gauss-Bonnet gravity: Stability, ringdown, and gravitational-wave emission

摘要

Gravitational waves emitted by distorted black holes---such as those arisingfrom the coalescence of two neutron stars or black holes---carry not onlyinformation about the corresponding spacetime but also about the underlyingtheory of gravity. Although general relativity remains the simplest, mostelegant and viable theory of gravitation, there are generic and robustarguments indicating that it is not the ultimate description of thegravitational universe. Here we focus on a particularly appealing extension ofgeneral relativity, which corrects Einstein's theory through the addition ofterms which are second order in curvature: the topological Gauss-Bonnetinvariant coupled to a dilaton. We study gravitational-wave emission from blackholes in this theory, and {\bf(i)} find strong evidence that black holes arelinearly (mode) stable against both axial and polar perturbations; {\bf(ii)}discuss how the quasinormal modes of black holes can be excited duringcollisions involving black holes, and finally {\bf(iii)} show that futureringdown detections with large signal-to-noise ratio would improve currentconstraints on the coupling parameter of the theory.