Spin-induced scalarization of Kerr black holes with a massive scalar field

TL;DR

This paper investigates how a massive scalar field influences the spin-induced scalarization of Kerr black holes within scalar-Gauss-Bonnet gravity, revealing that scalar mass affects the instability region but not the critical angular momentum.

Contribution

It introduces a linearized perturbation approach to study the impact of scalar field mass on Kerr black hole scalarization in scalar-Gauss-Bonnet gravity.

Findings

Increasing scalar mass raises the minimum coupling for scalarization.

Scalar mass reduces the instability region for Kerr black holes.

The critical angular momentum for instability remains unchanged.

Abstract

In the present paper we study the onset of the spin-induced scalarization of a Kerr black hole in scalar-Gauss-Bonnet gravity with a massive scalar field. Our approach is based on a (2+1) time evolution of the relevant linearized scalar field perturbation equation. We examine the region where the Kerr black hole becomes unstable giving rise to new scalarized rotating black holes with a massive scalar field. With increasing of the scalar field mass, the minimum value of the Gauss-Bonnet coupling parameter at which scalarization is possible, increases and thus the instability region shrinks. Interestingly, the introduction of scalar field mass does not change the critical minimal value of the black hole angular momentum $a_{\rm crit}/M$ where the instability of the Kerr black hole develops.