GeV excess and phenomenological astrophysics modeling

TL;DR

This paper investigates the GeV gamma-ray excess in the inner Galaxy using a spectral and morphological approach, confirming the excess and exploring its potential dark matter or astrophysical origins, highlighting the need for further astrophysical understanding.

Contribution

The study introduces an alternative spectral-morphological method to analyze the GeV excess, challenging the assumption of purely dark matter origin and emphasizing astrophysical explanations.

Findings

Confirmed the presence of the GeV excess in the inner Galaxy.

The excess exhibits a central cusp consistent with dark matter annihilation.

Astrophysical processes in the Galactic disk could also produce similar spectral features.

Abstract

Predefined spatial templates to describe the background of $\gamma$-ray emission from astrophysical processes, like cosmic ray interactions, are used in previous searches for the $\gamma$-ray signatures of annihilating galactic dark matter. In this proceeding, we investigate the GeV excess in the inner Galaxy using an alternative approach, in which the astrophysical components are identified solely by their spectral and morphological properties. We confirm the reported GeV excess and derive related parameters for dark matter interpretation, which are consistent with previous results. We investigate the morphology of this spectral excess as preferred by the data only. This emission component exhibits a central Galaxy cusp as expected for a dark matter annihilation signal. However, Galactic disk regions with a morphology of that of the hot interstellar medium also host such a spectral component. This points to a possible astrophysical origin of the excess and requests a more detailed understanding of astrophysical $\gamma$-ray emitting processes in the galactic center region before definite claims about a dark matter annihilation signal can be made.