Pair creation in the vortex-driven magnetic fields of black holes

TL;DR

This paper investigates how pair creation in vortex-driven magnetic fields around black holes affects high-energy photon escape, showing that strong magnetic fields can suppress emission above certain energies depending on black hole mass and emission region.

Contribution

It introduces a model analyzing photon decay in magnetic fields near black holes, revealing energy thresholds for photon escape based on black hole parameters and emission location.

Findings

Photons above ~1 GeV at 10 Rg are trapped by magnetic fields.

High-energy photons (~250 GeV to 250 TeV) cannot escape depending on black hole mass.

Magnetic pair creation significantly influences observable high-energy radiation from black holes.

Abstract

We study the effects of pair creation on the radiation emerging from black holes under the assumption that the magnetic fields are vortex driven. In particular, for a sufficiently broad range of supermassive black holes, we investigated the energies at which photons undergo decay under the influence of a strong magnetic field, producing electron-positron pairs. Depending on particular physical parameters, it has been shown that in certain scenarios high or very high energy emission generated by black holes will be strongly suppressed, thus, will be unable to escape a zone where radiation is generated. In particular, photons with energies exceeding $\sim 1$ GeV will never leave the magnetosphere if they are generated at the scale 10$R_g$ and the threshold is of the order of $1$ TeV, if the emission is produced at $\sim 100\; R_g$. Analysing the process versus the black hole mass, assuming the region $100\; R_g$, it has been shown that for the considered lowest mass, the photons with energies $250$ GeV will never leave the black hole and for the considered highest mass the corresponding value is $\sim 250$ TeV.