Anisotropy of Cosmic Background Photons from Annihilating/Decaying Dark Matter

TL;DR

This paper develops a detailed method to compute the angular power spectrum of cosmic background photons from dark matter decay or annihilation, emphasizing the importance of detector energy resolution.

Contribution

It introduces a comprehensive formulation for the angular power spectrum considering line photon emissions and detector energy resolution effects.

Findings

Applied the formulation to data from infrared, optical, X-ray, and gamma-ray telescopes.

Highlighted the necessity of accounting for energy resolution in spectral analysis.

Provided a framework for future observational constraints on dark matter properties.

Abstract

We provide a detailed formulation for calculating the angular power spectrum of the cosmic background photons arising from the dark matter decay or annihilation in a comprehensive manner. We pay particular attention to the case of dark matter decaying or annihilating into line photons. It is pointed out that taking account of the energy resolution of the detector is essential to correctly evaluate the angular power spectrum. We apply our formulation to the observational data from infrared, optical, X-ray and gamma-ray telescopes.