Interior marginally outer trapped surfaces in Hayward black holes

Abstract

We locate interior marginally outer trapped and marginally outer trapped open surfaces (MOTS/MOTOS) in the regular Haward metric with parameter $b$ for which a critical (extremal) value $b=b_c$ demarcates when the spacetime admits no horizon and when it admits inner and outer horizons. We identify self-intersecting MOTS which occur in pairs. For $b$ close to the critical value, there are no self-intersecting MOTS/MOTOS, and one can fine-tune $b$ so that the interior contains only near-spherical MOTS. We also show that in a neighborhood of the inner horizon for certain values of $b$, upon reduction of the problem to a singular Sturm-Liouville problem, the locations of the MOTS are given by hypergeometric functions, the eigenspace of the operator for which is complete, not discrete, and discontinuous.

21 pages, 15 figures. Accepted in International Journal of Modern Physics D