Numerical estimation of the escaping flux of massless particles created in collisions around a Kerr black hole

TL;DR

This paper numerically estimates the flux of massless particles escaping from collisions near a Kerr black hole, revealing spectral features that depend on dark matter properties and distribution.

Contribution

It introduces a numerical method to calculate escape fractions of particles from black hole collisions considering dark matter annihilation.

Findings

Energy spectrum shows two Lorentz shifted peaks.

Peak separation depends on dark matter density profile.

Method estimates emergent flux based on collision dynamics near black holes.

Abstract

The geodesics of massless particles produced in collisions near a rotating black hole are solved numerically and a Monte Carlo integration of the momentum distribution of the massless particles is performed to calculate the fraction that escape the black hole to infinity. A distribution of in falling dark matter particles, which are assumed to annihilate to massless particles, is considered and an estimate of the emergent flux from the collisions is made. The energy spectrum of the emergent particles is found to contain two Lorentz shifted peaks centred on the mass of the dark matter. The separation of the peaks is found to depend on the density profile of the dark matter and could provide information about the size of the annihilation plateau around a black hole and the mass of the dark matter particle.