Lights, Camera, Axion: Tracing Axions from Supernovae in the Diffuse $\gamma$-ray Sky

TL;DR

This paper models axion production in supernovae and their conversion into gamma rays across multiple astrophysical environments, deriving constraints on axion properties from gamma-ray observations and forecasting future telescope sensitivities.

Contribution

It introduces a comprehensive framework for calculating the diffuse gamma-ray flux from supernova-produced axions, including all relevant magnetic field environments, and provides new constraints and forecasts.

Findings

Derived competitive constraints on axion-photon coupling from gamma-ray data.

Developed a unified model for axion-photon conversion across multiple astrophysical magnetic fields.

Forecasted improved sensitivity of future gamma-ray telescopes to axion signals.

Abstract

Axions produced copiously in core-collapse supernovae can convert into photons as they propagate through various astrophysical magnetic fields. The cumulative emission from the cosmic population of supernovae can therefore generate a diffuse gamma-ray signal through axion-photon conversion. In this work, we develop a comprehensive framework to compute the diffuse gamma-ray flux by modeling axion production in supernovae and, \textit{for the first time}, consistently accounting for their conversion into photons across all relevant magnetic field environments - progenitor, host galaxy, intergalactic medium, and the Milky Way - together with an updated cosmic star formation rate. Using measurements of the diffuse gamma-ray sky from COMPTEL, EGRET, and \textit{Fermi}-LAT, we derive competitive constraints on the axion-photon coupling over a wide range of axion masses. We further forecast the sensitivity of upcoming MeV gamma-ray telescopes to this diffuse signal using a Fisher forecast analysis.