Axion-photon multimessenger astronomy with giant flares

Abstract

We treat prospects for multimessenger astronomy with giant flares (GFs), a rare transient event featured by magnetars that can be as luminous as a hundred of the brightest supernovae ever observed. The beamed photons could correlate with an axion counterpart via resonant conversion in the magnetosphere. In a realistic parameter space, we find that the sensitivity limit to galactic GFs for currently viable experiments is ${\mathrm{g}}_{\varphi \gamma }\gtrsim \mathrm{several}\times 10^{-13}$ GeV${}^{-1}$ \& ${\mathrm{g}}_{\varphi e}\gtrsim \mathrm{few}\times 10^{-12}$. We rule out the compatibility of axion flares with the recent XENON1T excess only due to the time persistence of the signal.

Comments: 7 pages, 3 figures