A gravitating Yang-Mills instanton

Abstract We present an asymptotically flat, spherically symmetric, static, globally regular and horizonless solution of SU(2)-gauged N = 1 $$ \mathcal{N}=1 $$ , d = 5 supergravity. The SU(2) gauge field is that of the BPST instanton. We argue that this solution, analogous to the global monopoles found in d = 4 N = 2 $$ \mathcal{N}=2 $$ and N = 4 $$ \mathcal{N}=4 $$ gauged supergravities, describes the field of a single string-theory object which does not contribute to the entropy of black holes when we add it to them and show that it is, indeed, the dimensional reduction on T5 of the gauge 5-brane. We investigate how the energy of the solution is concentrated as a function of the instanton’s scale showing that it never violates the hoop conjecture although the curvature grows unboundedly in the zero scale limit