On the cosmic-ray distribution in the Galactic Center region: New insights from H.E.S.S

TL;DR

This study uses H.E.S.S. gamma-ray data to analyze the diffuse cosmic-ray emission in the Galactic Center, supporting a steady injection model and identifying a spectral transition around 10-20 TeV.

Contribution

It provides new insights into the cosmic-ray distribution and spectral features in the Galactic Center using advanced modeling and likelihood fitting techniques.

Findings

Data consistent with a steady cosmic-ray injection near the Galactic center.

Identified a spectral transition near 10-20 TeV in the ridge emission.

Supported a diffusion model for cosmic rays in the Central Molecular Zone.

Abstract

We performed a spectro-morphological analysis of the diffuse emission in the Galactic center region with H.E.S.S. gamma-ray data. We relied on templates to model the diffuse emissions (the Galactic center ridge and the foreground component) and on a 3D likelihood fitting approach. We first assessed the validity of a continuous injection scenario near the Galactic center by investigating possible deviations from a 1/r profile of the cosmic-ray distribution and potential spectral variations within the Galactic center ridge. We found the data can appropriately be described by a scenario in which a steady source near the Galactic center continuously injects cosmic rays which diffuse through the Central Molecular Zone. We then derived the best-fit spectral parameters of the Galactic center ridge emission and we found a spectral transition near 10-20 TeV.