Parker Bounds on Monopoles with Arbitrary Charge from Galactic and Primordial Magnetic Fields

TL;DR

This paper derives astrophysical bounds on magnetic monopoles with arbitrary charges by analyzing their effects on galactic, seed, and primordial magnetic fields, and evaluates their potential as dark matter candidates.

Contribution

It provides a comprehensive analysis of Parker bounds for monopoles with arbitrary charges, including minicharged monopoles and black holes, across different astrophysical contexts.

Findings

Monopoles with Dirac charge are constrained by seed galactic magnetic fields.

Minicharged monopoles are constrained by primordial magnetic fields.

Magnetic black holes are constrained by dark matter density.

Abstract

We present a comprehensive study of Parker-type bounds on magnetic monopoles with arbitrary magnetic charge, including minicharged monopoles and magnetic black holes. We derive the bounds based on the survival of galactic magnetic fields, seed magnetic fields, as well as primordial magnetic fields. We find that monopoles with different magnetic charges are best constrained by different astrophysical systems: while monopoles with a Dirac charge are tightly constrained by seed galactic magnetic fields, minicharged monopoles are strongly constrained by primordial magnetic fields, and magnetic black holes by the density of dark matter. We also assess the viability of the various types of monopoles as dark matter, by studying whether they can cluster with galaxies hosting magnetic fields.