Bulk scalar emission from a rotating black hole pierced by a tense brane

TL;DR

This paper investigates scalar field emission from a six-dimensional rotating black hole with a brane, analyzing how brane tension and rotation influence emission spectra and superradiance effects.

Contribution

It introduces a numerical method to compute emission spectra considering finite brane tension and rotation, extending previous analyses to a wider frequency range.

Findings

Finite brane tension suppresses emission rates.

Higher rotation enhances high-frequency emission and angular momentum transfer.

Superradiance increases emission at high frequencies with rotation.

Abstract

We study the emission of scalar fields into the bulk from a six-dimensional rotating black hole pierced by a 3-brane. We determine the angular eigenvalues in the presence of finite brane tension by using the continued fraction method. The radial equation is integrated numerically, giving the absorption probability (graybody factor) in a wider frequency range than in the preexisting literature. We then compute the power and angular momentum emission spectra for different values of the rotation parameter and brane tension, and compare their relative behavior in detail. As is expected from the earlier result for a nonrotating black hole, the finite brane tension suppresses the emission rates. As the rotation parameter increases, the power spectra are reduced at low frequencies due to the smaller Hawking temperature and are enhanced at high frequencies due to superradiance. The angular momentum spectra are enhanced over the whole frequency range as the rotation parameter increases. The spectra and the amounts of energy and angular momentum radiated away into the bulk are thus determined by the interplay of these effects.