Gamma-ray and Synchrotron Radiation from Dark Matter annihilations in Ultra-faint Dwarf Galaxies

TL;DR

This study investigates gamma-ray and radio emissions from ultra-faint dwarf galaxies to constrain dark matter annihilation properties, utilizing observational data and assessing future telescope sensitivities.

Contribution

It provides model-independent upper limits on dark matter annihilation cross sections from multiple UFDs using gamma-ray and radio data, and evaluates future detection prospects.

Findings

Established upper limits on dark matter annihilation cross section.

Analyzed the impact of astrophysical uncertainties on these limits.

Assessed the potential of the Square Kilometer Array for future detection.

Abstract

The very large (100-1000) mass-to-light ratio applicable to the ultra-faint dwarf galaxies (UFDs) implies a high concentration of dark matter, thus rendering them ideal theatres for indirect signatures of dark matter. In this paper, we consider 14 recently discovered UFDs and study the electromagnetic radiation emanating from them over a wide range, from gamma ray down to radio frequencies. We analyze the Fermi-LAT data on high energy gamma rays and radio fluxes at the GMRT and VLA to obtain upper limits on annihilation cross section $\langle\sigma v\rangle$ in a model independent way. We further discuss the sensitivity of the Square Kilometer Array radio telescope in probing the synchrotron radiation from the aforementioned UFDs. We also investigate the dependences of the said upper limits on the uncertainties in the determination of various astrophysical parameters.