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On the leptonic contribution to the ultra high-energy diffuse gamma-ray background
- Publication Year :
- 2024
-
Abstract
- The ultra high-energy (UHE) diffuse gamma-ray background holds important information on the propagation of cosmic rays in the Galaxy. However, its measurements suffer from a contamination from unresolved sources whose importance remains unclear. In this Letter, we propose a novel data-driven estimate of the contribution of unresolved leptonic sources based on the information present in the ATNF and the LHAASO catalogs. We find that in the inner Galaxy at most $\sim60\%$ of the diffuse flux measured by LHAASO at $10\,\rm{TeV}$ may originate from unresolved leptonic sources, and this fraction drops with energy to less than $20\%$ at $100\,\rm{TeV}$. In the outer Galaxy, the contribution of unresolved leptonic sources is always subdominant. It is less than $\sim 20\%$ at $10\,\rm{TeV}$ and less than $\sim 8\%$ above $\sim25\,\rm{TeV}$. We conclude that the UHE diffuse background should be dominated by photons from a hadronic origin above a few tens of $\rm{TeV}$.<br />Comment: 7 pages, 4 figures
- Subjects :
- Astrophysics - High Energy Astrophysical Phenomena
Subjects
Details
- Database :
- arXiv
- Publication Type :
- Report
- Accession number :
- edsarx.2407.20186
- Document Type :
- Working Paper