Dark matter properties implied by gamma ray interstellar emission models

TL;DR

This study uses gamma ray residuals and Bayesian analysis to infer dark matter properties, highlighting the impact of interstellar emission modeling on these inferences.

Contribution

It introduces a Bayesian framework to evaluate dark matter models against gamma ray residuals across multiple interstellar emission scenarios.

Findings

Four scenarios are compatible with the dark matter model.

Preferred dark matter mass range is 100-500 GeV with top quark annihilation.

Dark matter properties are highly sensitive to interstellar emission modeling.

Abstract

We infer dark matter properties from gamma ray residuals extracted using eight different interstellar emission scenarios proposed by the Fermi-LAT Collaboration to explain the Galactic Center gamma ray excess. Adopting the most plausible simplified ansatz, we assume that the dark matter particle is a Majorana fermion interacting with standard fermions via a scalar mediator. Using this theoretical hypothesis and the Fermi residuals we calculate Bayesian evidences, including Fermi-LAT exclusion limits from 15 dwarf spheroidal galaxies as well. Our Bayes factors single out four of the Fermi scenarios as compatible with the simplified dark matter model. In the most preferred scenario the dark matter (mediator) mass is in the 100-500 (1-200) GeV range and its annihilation is dominated by top quark final state. Less preferred but still plausible is annihilation into b\bar{b} and tau^+tau^- final states with an order of magnitude lower dark matter mass. Our conclusion is that the properties of dark matter extracted from gamma ray data are highly sensitive to the modeling of the interstellar emission.