Gravitational Properties of the Monopole Bag

Processes such as phase transitions and symmetry breaking in the early universe are well-studied and thought to be instrumental in giving rise to the nature and composition that we observe. In particular, axionic cosmologies constitute a class of phenomenologically rich models with symmetry breaking, UV relevance, and potentially detectable consequences. In the case where monopoles are also present in such a background, the axion profile may be deformed; it is possible to construct a "monopole bag" state composed of a central monopole within a closed axion domain wall. We consider the gravitational properties of this hybrid defect, and find a both horizon-less and a black hole-like final state can result as remnants of the monopole-domain wall system after gravitational collapse for different input parameters