Off-Equatorial Orbits around Magnetically Charged Black Holes

TL;DR

This paper characterizes stable off-equatorial circular orbits around magnetically charged black holes, revealing unique features and potential observational signatures that distinguish them from electrically charged black holes.

Contribution

It provides the first complete analytic and numerical analysis of off-equatorial orbits around magnetically charged black holes, including effects of rotation and synchrotron radiation.

Findings

Charged particles can have significant latitude deviations at the ISCO.

Off-equatorial orbits are stable under synchrotron emission.

Such orbits are absent in electrically charged Kerr-Newman black holes.

Abstract

We present a complete characterization of stable, off-equatorial circular orbits around magnetically charged black holes (MBHs). For a static, spherically symmetric MBH, we derive an exact analytic expression for the orbital latitude theta as a function of radius r and we analyze the effect of synchrotron radiation. We show that charged particles such as electrons and protons can exhibit O(1) latitude deviations at the ISCO radius and remain stable under synchrotron emission even for extremely small values of the black hole magnetic charge. We then extend the analysis to rotating MBHs, numerically computing the prograde and retrograde orbital branches and demonstrating how frame-dragging modifies their structure and stability regions. We show that these off-equatorial orbits are a unique feature of the magnetic charge, being forbidden in the analogous electrically charged Kerr-Newman spacetime. Our results suggest that environments surrounding magnetically charged black holes can exhibit distinctive phenomenological signatures, potentially offering a way to constrain the magnetic charge of astrophysical black holes.