Detecting Axion Dark Matter through the Radio Signal from Omega Centauri

TL;DR

This study proposes using radio signals from the globular cluster Omega Centauri to detect axion dark matter, leveraging upcoming radio telescope capabilities to explore new parameter space for axion-photon coupling.

Contribution

It introduces a novel method to probe axion dark matter using the combined radio signals from all neutron stars and white dwarfs in Omega Centauri.

Findings

Effective probing of axion-photon coupling up to 10^{-14}–10^{-15} GeV^{-1}.

Sensitivity surpasses single star observations by two to three and a half orders of magnitude.

Utilizes 100 hours of observations with SKA phase 1 and LOFAR.

Abstract

As a well-motivated dark matter candidate, axions can be detected through the axion-photon resonant conversion in the magnetospheres of magnetic white dwarf stars or neutron stars. In this work, we utilize Omega Centauri, which is the largest globular cluster in the Milky Way and is suggested to be the remnant core of a dwarf galaxy, to probe the axion dark matter through radio signals that originate from all the neutron stars and magnetic white dwarf stars in it. With 100 hours of observation, the combination of SKA phase 1 and LOFAR can effectively probe the parameter space of the axion-photon coupling $g_{a\gamma}$ up to $10^{-14}\sim 10^{-15}~\text{GeV}^{-1}$ for the axion mass range of $0.1\sim 30 ~\mu\text{eV}$. Depending on the choice of neutron star evolution model, this limitation is two or three and a half orders of magnitude higher than that of the single neutron star or magnetic white dwarf.