Robust identification of isotropic diffuse gamma rays from Galactic dark matter

TL;DR

This paper proposes a method to identify gamma rays from Galactic dark matter substructure by analyzing the energy dependence of the angular power spectrum in gamma-ray data, aiding in distinguishing it from extragalactic background.

Contribution

It introduces a novel approach using angular power spectrum energy dependence to detect Galactic dark matter signals in gamma-ray observations.

Findings

Angular power spectrum varies with energy if dark matter contributes.

Method can differentiate Galactic dark matter from extragalactic background.

Applicable to Fermi Gamma-ray Space Telescope data.

Abstract

Dark matter annihilation in Galactic substructure will produce diffuse gamma-ray emission of remarkably constant intensity across the sky, making it difficult to disentangle this Galactic dark matter signal from the extragalactic gamma-ray background. We show that if Galactic dark matter contributes a modest fraction of the measured emission in an energy range accessible to the Fermi Gamma-ray Space Telescope, the energy dependence of the angular power spectrum of the total measured emission could be used to confidently identify gamma rays from Galactic dark matter substructure.