Particle motion around magnetized black holes: Preston-Poisson space-time

TL;DR

This paper studies how a surrounding structure's tidal forces in Preston-Poisson space-time affect particle and light trajectories around magnetized black holes, revealing significant changes in orbital and optical properties.

Contribution

It introduces the Preston-Poisson metric with a tidal parameter, extending previous models to analyze particle motion in magnetized black hole environments.

Findings

Tidal forces increase the radius of circular orbits.

Tidal forces raise the binding energy of particles near the black hole.

Tidal forces enlarge the minimal approach distance, time delay, and bending angle for light.

Abstract

We analyze motion of massless and massive particles around black holes immersed in an asymptotically uniform magnetic field and surrounded by some mechanical structure, which provides the magnetic field. The space-time is described by Preston-Poisson metric, which is the generalization of the well-known Ernst metric with a new parameter, tidal force, characterizing the surrounding structure. The Hamilton-Jacobi equations allow separation of variables in the equatorial plane. The presence of tidal force from surroundings considerably changes parameters of the test particle motion: it increases the radius of circular orbits of particles, increases the binding energy of massive particles going from a given circular orbits to the innermost stable orbit near black hole. In addition, it increases the distance of minimal approach, time delay and bending angle for a ray of light propagating near black hole.