Shaping black holes with free fields

Abstract

Starting from a metric Ansatz permitting a weak version of Birkhoff's theorem we find static black hole solutions including matter in the form of free scalar and p-form fields, with and without a cosmological constant Λ. Single p-form matter fields permit multiple possibilities, including dyonic solutions, self-dual instantons and metrics with Einstein-Kälher horizons. The inclusion of multiple p-forms on the other hand, arranged in a homogeneous fashion with respect to the horizon geometry, permits the construction of higher dimensional dyonic p-form black holes and four dimensional axionic black holes with flat horizons, when Λ < 0. It is found that axionic fields regularize black hole solutions in the sense, for example, of permitting regular - rather than singular - small mass Reissner-Nordstrom type black holes. Their cosmic string and Vaidya versions are also obtained. © SISSA 2012.