Addressing γ-ray emissions from dark matter annihilations in 45 Milky Way satellite galaxies and in extragalactic sources with particle dark matter models

The mass-to-luminosity ratio of the dwarf satellite galaxies in the Milky Way suggests that these dwarf galaxies may contain substantial dark matter. The dark matter at the dense region such as within or at the vicinity of the centres of these dwarf galaxies may undergo the process of self-annihilation and produce gamma-rays as the end product. The satellite borne gamma-ray telescope such as Fermi-LAT reported the detection of gamma-rays from around 45 Dwarf Spheroidals (dSphs) of Milky Way. In this work, we consider particle dark matter models described in the literature and after studying their phenomenologies, we calculate the gamma-ray fluxes from the self-annihilation of the dark matter within the framework of these models in case of each of these 45 dSphs. We then compare the computed results with the observational upper bounds for gamma-ray flux reported by Fermi-LAT and Dark Energy Survey for each of the 45 dSphs. The fluxes are calculated by adopting different dark matter density profiles. We then extend similar analysis for the observational upper bounds given by Fermi-LAT for the continuum gamma-ray fluxes originating from extragalactic sources.

Automated summary

This study investigates the potential presence of dark matter and its self-annihilation in dwarf satellite galaxies of the Milky Way, calculating gamma-ray fluxes based on different dark matter models and comparing them with observational upper bounds reported by Fermi-LAT and Dark Energy Survey. Additionally, the analysis extends to the observational upper bounds for continuum gamma-ray fluxes from extragalactic sources given by Fermi-LAT.