Magnetized black holes: the role of rotation, boost, and accretion in twisting the field lines and accelerating particles

TL;DR

This paper investigates how the combined effects of black hole rotation, magnetic field misalignment, and particle motion influence particle acceleration and escape in black hole accretion systems, revealing enhanced escape probabilities with retrograde motion.

Contribution

It extends previous models by including retrograde particle orbits and analyzing their impact on particle acceleration and escape in magnetized, rotating black hole environments.

Findings

Counter-rotation increases particle escape probability.

Retrograde orbits enable higher particle energies.

Magnetic field misalignment affects acceleration efficiency.

Abstract

Combined influence of rotation of a black hole and ambient magnetic fields creates conditions for powerful astrophysical processes of accretion and outflow of matter which are observed in many systems across the range of masses; from stellar-mass black holes in binary systems to supermassive black holes in active galactic nuclei. We study a simplified model of outflow of electrically charged particles from the inner region of an accretion disk around a spinning (Kerr) black hole immersed in a large-scale magnetic field. In particular, we consider a non-axisymmetric magnetosphere where the field is misaligned with the rotation axis. In this contribution we extend our previous analysis of acceleration of jet-like trajectories of particles escaping from bound circular orbits around a black hole. While we have previously assumed the initial setup of prograde (co-rotating) orbits, here we relax this assumption and we also consider retrograde (counter-rotating) motion. We show that the effect of counter-rotation may considerably increase the probability of escape from the system, and it allows more efficient acceleration of escaping particles to slightly higher energies compared to the co-rotating disk.