Black hole scalarization induced by the spin: 2+1 time evolution

Abstract

Scalarization is a very interesting phenomenon allowing a compact object to be endowed with scalar hair while leaving all the predictions in the weak field limit unaltered. In Gauss-Bonnet gravity, the source of the scalar field can be the curvature of the spacetime. It was recently shown that for a particular type of coupling function between the scalar field and the Gauss-Bonnet invariant, spin-induced black hole scalarization is possible. In the present paper, we study this phenomenon by performing a 2+1 time evolution of the relevant linearized scalar field perturbation equation and examine the region where the Kerr black hole becomes unstable, giving rise to new scalarized rotating black holes. This is a direct numerical approach to study the development of spin-induced scalarization, and it can serve as an independent check of previously published results.