Warped- AdS3 black holes with scalar halo

Abstract

We construct a stretched (aka warped) anti-de Sitter black hole in three dimensions supported by a real scalar field configuration. The latter is regular everywhere outside and on the horizon. No-hair theorems in three dimensions demand the matter be coupled to the curvature in a nonminimal way; however, this coupling can still be of the Horndeski type, i.e. yielding second order field equations similar to those appearing in the context of Galileon theories. These warped-anti-de Sitter black holes exhibit interesting thermodynamical properties, such as finite Hawking temperature and entropy. We compute the black hole entropy in the gravity theory and speculate on the possibility of this to admit a microscopic description in terms of a dual (warped) conformal field theory. We also discuss the inner and outer black hole mechanics.