Searching for Light in the Darkness: Bounds on ALP Dark Matter with the optical MUSE-Faint survey

TL;DR

This study uses optical spectroscopic data from the MUSE-Faint survey to set new constraints on axion-like particle dark matter by searching for their radiative decay signals in the dwarf galaxy Leo T, significantly improving previous bounds.

Contribution

The paper provides the first constraints on ALP dark matter in the 2.7-5.3 eV mass range using optical spectroscopy, surpassing prior limits by over an order of magnitude.

Findings

Established new bounds on ALP-two-photon coupling in the 2.7-5.3 eV mass range.

Demonstrated the effectiveness of optical spectroscopy in probing ALP dark matter.

Improved existing limits on ALP properties by more than tenfold.

Abstract

We use MUSE spectroscopic observations of the dwarf spheroidal galaxy Leo T between 470 and 935 nm to search for radiative decays of axion like particles (ALPs). Under the assumption that ALPs constitute the dark matter component of the Leo T halo, we derive bounds on the effective ALP-two-photon coupling. We improve existing limits by more than one order of magnitude in the ALP mass range 2.7-5.3 eV.