Kerr black holes without primary hairs

Abstract

We present a class of regular axisymmetric black hole geometries fully characterized by the parameters

and possessing the Kerr event horizon. This family interpolates between regular spacetimes, configurations with integrable singularities, and the Kerr solution as a limiting case. Its main features are: (i) the existence of quasi-extremal configurations without requiring

$$a \approx \mathcal{M}$$ a ≈ M

; and (ii) a possible framework toward an analytical description of Kerr black hole formation from an initially regular configuration.