Heating up the Galaxy with Hidden Photons

TL;DR

This paper investigates how ultra-light hidden photon dark matter influences the ionized interstellar medium, revealing it as a significant heating source and setting new constraints on hidden photon properties.

Contribution

It demonstrates that ultra-light hidden photon dark matter can heat the interstellar medium and establishes new bounds on kinetic mixing at very low masses.

Findings

Hidden photon dark matter heats the interstellar medium.

Galactic plasma shielding complicates direct detection.

New bounds on hidden photon kinetic mixing down to 10^{-20} eV.

Abstract

We elaborate on the dynamics of ionized interstellar medium in the presence of hidden photon dark matter. Our main focus is the ultra-light regime, where the hidden photon mass is smaller than the plasma frequency in the Milky Way. We point out that as a result of the Galactic plasma shielding direct detection of ultra-light photons in this mass range is especially challenging. However, we demonstrate that ultra-light hidden photon dark matter provides a powerful heating source for the ionized interstellar medium. This results in a strong bound on the kinetic mixing between hidden and regular photons all the way down to the hidden photon masses of order $10^{-20}$ eV.