Galactic magnetic fields seeded by ultralight dark photons

TL;DR

This paper proposes that ultralight dark photons could generate seed magnetic fields in galaxies, which are amplified by dynamo processes to match observed galactic magnetic field strengths.

Contribution

It introduces a novel mechanism where ultralight dark photons seed galactic magnetic fields, bridging dark matter physics and astrophysical magnetic phenomena.

Findings

Dark photons can produce seed magnetic fields of about 10^{-20} G.

These seed fields are sufficient for dynamo amplification to observed galactic magnetic strengths.

The generated fields are consistent with current astrophysical observations.

Abstract

In this work, we show that ultralight dark photons, which couple to the Standard Model photon through kinetic mixing, can potentially source galactic scale magnetic fields. Although these magnetic fields would be too weak to detect at present in galaxies due to plasma screening effects, we show that dark photons can provide the seed magnetic field strength ($10^{-20}$ G) required for dynamo amplification in galaxies. Such dynamo-amplified magnetic fields are consistent with observations of $\mu$G strength galactic magnetic fields.