Black hole in a model with dilaton and monopole fields

摘要

We present an exact black hole solution in a model having besides gravity a dilaton and a monopole field. The solution has three free parameters, which can be identified with the monopole charge, the ADM mass, and the dilaton charge. The metric is asymptotically flat and has two horizons and irremovable singularity only at r = 0. The dilaton field is singular only at r = 0. The dominant and the strong energy condition are satisfied outside and on the external horizon. According to a formulation of the no hair conjecture, the solution is "hairy." Also the well-known GHS-GM solution is obtained from our solution for certain values of its parameters.