Dwarf Galaxy $\gamma$-excess and 3.55 keV X-ray Line In A Nonthermal Dark Matter Model

TL;DR

This paper presents a nonthermal dark matter model that simultaneously explains the gamma-ray excess observed in Reticulum II and the 3.55 keV X-ray line, fitting observational data with an extended scalar sector.

Contribution

The model introduces two additional scalars with specific masses to account for both signals, along with a new seed mechanism and Boltzmann equations for relic density calculation.

Findings

Successfully fits RetII gamma-ray data

Explains 3.55 keV X-ray line with new scalars

Maintains consistency with other indirect limits

Abstract

Recent data from Reticulum II (RetII) require the energy range of the FermiLAT $\gamma$-excess to be $\sim$ $2-10$ GeV. We adjust our unified nonthermal Dark Matter (DM) model to accommodate this. We have two extra scalars beyond the Standard Model to also explain 3.55 keV X-ray line. Now the mass of the heavier of them has to be increased to lie around 250 GeV, while that of the lighter one remains at 7.1 keV. This requires a new seed mechanism for the $\gamma$-excess and new Boltzmann equations for the generation of the DM relic density. All concerned data for RetII and the X-ray line can now be fitted well and consistency with other indirect limits attained.