Supernova axions convert to gamma-rays in magnetic fields of progenitor stars

TL;DR

This paper extends constraints on axion properties by analyzing supernova SN1987A data and proposes a new gamma-ray satellite to detect axions from future supernovae and neutron star mergers.

Contribution

It introduces a method to constrain higher mass axions using supernova progenitor magnetic fields and proposes the GALAXIS satellite for future axion detection.

Findings

Constraints on axion mass up to 10^{-3} eV from SN1987A data.

Potential detection of QCD axions above 50 μeV from future supernovae.

Proposal of the GALAXIS satellite for comprehensive axion searches.

Abstract

It has long been established that axions could have been produced within the nascent proto-neutron-star formed following the type II supernova SN1987A, escaped the star due to their weak interactions, and then converted to gamma-rays in the Galactic magnetic fields; the non-observation of a gamma-ray flash coincident with the neutrino burst leads to strong constraints on the axion-photon coupling for axion masses $m_a \lesssim 10^{-10}$ eV. In this work we use SN1987A to constrain higher mass axions, all the way to $m_a \sim 10^{-3}$ eV, by accounting for axion production from the Primakoff process, nucleon bremsstrahlung, and pion conversion along with axion-photon conversion on the still-intact magnetic fields of the progenitor star. Moreover, we show that gamma-ray observations of the next Galactic supernova, leveraging the magnetic fields of the progenitor star, could detect quantum chromodynamics axions for masses above roughly 50 $\mu$eV, depending on the supernova. We propose a new full-sky gamma-ray satellite constellation that we call the GALactic AXion Instrument for Supernova (GALAXIS) to search for such future signals along with related signals from extragalactic neutron star mergers.