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

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.

Comments: 8 eps figures, 1 Table, 7 pages. The paper has been completely rewritten with additional references and discussions of indirect constraints from AMS-02 and ANTARES data. Basic results remain unchanged. Version accepted for publication in Europhysics Letters