Dark Matter in $\gamma$ lines: Galactic Center vs dwarf galaxies

TL;DR

This paper evaluates CTA's ability to detect dark matter annihilation signals in gamma-ray lines from the Galactic Center and dwarf spheroidal galaxies, highlighting the potential of dSphs as more promising targets for certain dark matter profiles.

Contribution

It introduces the first comparison of CTA sensitivities to dark matter in gamma-ray lines from both the Galactic Center and dwarf spheroidal galaxies, considering core radius uncertainties.

Findings

Dwarf spheroidal galaxies may be better targets than the Galactic Center for certain dark matter profiles.

CTA sensitivities are projected to test models like the supersymmetric Wino and Minimal Dark Matter fiveplet.

The analysis incorporates recent instrument response functions and background estimations, including diffuse photon components.

Abstract

We provide CTA sensitivities to Dark Matter (DM) annihilation in $\gamma$-ray lines, from the observation of the Galactic Center (GC) as well as, for the first time, of dwarf Spheroidal galaxies (dSphs). We compare the GC reach with that of dSphs as a function of a putative core radius of the DM distribution, which is itself poorly known. We find that the currently best dSph candidates constitute a more promising target than the GC, for core radii of one to a few kpc. We use the most recent instrument response functions and background estimations by CTA, on top of which we add the diffuse photon component. Our analysis is of particular interest for TeV-scale electroweak multiplets as DM candidates, such as the supersymmetric Wino and the Minimal Dark Matter fiveplet, whose predictions we compare with our projected sensitivities.