Confronting Galactic center and dwarf spheroidal gamma-ray observations with cascade annihilation models

TL;DR

This study examines whether cascade annihilation dark matter models can explain the gamma-ray signals from the Galactic center while remaining consistent with null results from dwarf spheroidal galaxies, considering astrophysical uncertainties.

Contribution

It provides a model-independent analysis of cascade annihilation dark matter models, assessing their compatibility with gamma-ray observations and highlighting the impact of astrophysical uncertainties.

Findings

Constraints are strong under canonical assumptions.

Uncertainties in dark matter distribution weaken constraints.

Dark matter interpretations remain viable across various mass scales.

Abstract

Many particle dark matter models predict that the dark matter undergoes cascade annihilations, i.e. the annihilation products are 4-body final states. In the context of model-independent cascade annihilation models, we study the compatibility of the dark matter interpretation of the Fermi- LAT Galactic center gamma-ray emission with null detections from dwarf spheroidal galaxies. For canonical values of the Milky Way density profile and the local dark matter density, we find that the dark matter interpretation to the Galactic center emission is strongly constrained. However, uncertainties in the dark matter distribution weaken the constraints and leave open dark matter interpretations over a wide range of mass scales.