Constraining meV Axion Dark Matter with ALMA Observations of the Galactic Center Magnetar SGR 1745-2900

TL;DR

This study uses ALMA radio observations of the Galactic Center magnetar to search for axion dark matter signals, setting new constraints on axion-photon coupling in the meV mass range.

Contribution

First to constrain QCD axion parameter space near the meV scale using ALMA observations of a magnetar at the Galactic Center.

Findings

No significant axion signals detected.

Constraints on axion-photon coupling of $g_{\gamma}\gtrsim 2\times10^{-13}$ GeV$^{-1}$.

Effective probing of the axion mass range 0.55-0.62 meV.

Abstract

We report a mm-wave search for axions from the magnetar SGR 1745-2900, based on 4.8 h of ALMA observations. No statistically significant features are detected between 133.99-135.78, 135.91-137.70, 145.99-147.78, and 147.99-149.78 GHz. Interpreting this null result via resonant conversion with a state-of-the-art star model and the dark-matter density expected at the Galactic Center, we constrain the axion-photon coupling at the level of $g_{\gamma}\gtrsim 2\times10^{-13}$ GeV$^{-1}$ within 0.55-0.62 meV, accessing for the first time the QCD axion parameter space near the meV scale.