A Search for Axionic Dark Matter Using the Magnetar PSR J1745-2900

TL;DR

This study searches for axionic dark matter signals from the Galactic Center magnetar PSR J1745-2900 using radio spectra, setting new constraints on axion-photon coupling strength across several mass ranges.

Contribution

It provides the first observational limits on axion-photon coupling from magnetar spectra, improving constraints over previous experiments in specific mass ranges.

Findings

No significant spectral features detected.

Excluded axion models with certain couplings over multiple mass ranges.

Limits could be improved with stimulated emission modeling.

Abstract

We report on a search for dark matter axion conversion photons from the magnetosphere of the Galactic Center magnetar PSR J1745-2900 using spectra obtained from the Karl G. Jansky Very Large Array. No significant spectral features are detected. Using a hybrid model for PSR J1745-2900 and canonical assumptions about the dark matter density profile, we exclude axion models with axion-photon coupling $g_{a\gamma\gamma}$ > 6-34 x 10$^{-12}$ GeV$^{-1}$ with 95% confidence over the mass ranges 4.2-8.4, 18.6-26.9, 33.0-41.4, 53.7-62.1, and 126.0-159.3 $\mu$eV. If there is a dark matter cusp, the limits reduce to $g_{a\gamma\gamma}$ > 6-34 x 10$^{-14}$ GeV$^{-1}$, which overlap some axion models for the observed mass ranges > 33 $\mu$eV. These limits may be improved by modeling the stimulated emission that can boost the axion-photon conversion process.