Arising of trapped surfaces with nontrivial topology from colliding shock waves

The lightlike limit of boosted black hole solutions with one angular momentum is considered for D >= 4 dimensions. The boost is performed parallel to the angular momentum and the lightlike limit is done by means of perturbative expansions. We show that for D = 4 and D > 5 the lightlike limit cannot be extended inside the ring singularity. Then, for D = 5 we discuss the arising of trapped surfaces in the headon collision. We find that, inside the validity of the performed perturbative analysis, a trapped surface with topology R x S1 x S1 seems to appear over the past light cone of the collision below a critical value of the Kerr parameter.

Automated summary

The lightlike limit of boosted black hole solutions with one angular momentum in D >= 4 dimensions is investigated. Boost is performed parallel to the angular momentum and the lightlike limit is achieved through perturbative expansions. It is shown that the lightlike limit cannot extend inside the ring singularity for D = 4 and D > 5. In the case of D = 5, the emergence of trapped surfaces in head-on collision is discussed. It is found that, within the performed perturbative analysis, a trapped surface with the topology R x S1 x S1 seems to appear over the past light cone of the collision below a critical value of the Kerr parameter.