Current and Future Constraints on Dark Matter from Prompt and Inverse-Compton Photon Emission in the Isotropic Diffuse Gamma-ray Background

TL;DR

This paper analyzes current and future constraints on dark matter models using gamma-ray emissions, highlighting how improved observations could significantly tighten these constraints.

Contribution

It provides a comprehensive analysis of prompt and inverse-Compton gamma-ray constraints on dark matter, including forecasts for future sensitivity improvements with Fermi-LAT.

Findings

Current gamma-ray data constrains annihilating dark matter models.

Future observations could improve constraints by a factor of 2 to 3.

Blazar source resolution enhances the sensitivity of dark matter searches.

Abstract

We perform a detailed examination of current constraints on annihilating and decaying dark matter models from both prompt and inverse-Compton emission photons, including both model-dependent and model-independent bounds. We also show that the observed isotropic diffuse gamma-ray background (DGRB), which provides one of the most conservative constraints on models of annihilating weak-scale dark matter particles, may enhance its sensitivity by a factor of ~2 to 3 (95% C.L.) as the Fermi-LAT experiment resolves DGRB contributing blazar sources with five years of observation. For our forecasts, we employ the results of constraints to the luminosity-dependent density evolution plus blazar spectral energy distribution sequence model, which is constrained by the DGRB and blazar source count distribution function.