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First Detection of sub-PeV Diffuse Gamma Rays from the Galactic Disk: Evidence for Ubiquitous Galactic Cosmic Rays
M Amenomori1, Y W Bao2, X J Bi3
1Department of Physics, Hirosaki University, Hirosaki 036-8561, Japan.
Physical Review Letters
|April 23, 2021
Summary
Scientists detected diffuse gamma rays in the Galactic disk, providing evidence for high-energy cosmic ray acceleration within our galaxy. This finding supports the hadronic emission scenario for gamma-ray production.
Area of Science:
- * Astrophysics
- * Astroparticle Physics
Background:
- * The origin of high-energy cosmic rays remains a significant question in astrophysics.
- * Previous observations have primarily focused on discrete gamma-ray sources.
Purpose of the Study:
- * To report the first detection of diffuse gamma rays in the 100 TeV to 1 PeV energy range.
- * To investigate the origin of these high-energy gamma rays within the Galactic disk.
Main Methods:
- * Analysis of gamma-ray data from the Galactic disk.
- * Comparison of observed gamma-ray flux with theoretical emission models.
Main Results:
- * Detection of diffuse gamma rays between 100 TeV and 1 PeV.
- * Gamma rays above 398 TeV are spatially extended and not associated with known point sources.
- * Observations align with the hadronic emission scenario involving proton-interstellar medium interactions.
Conclusions:
- * Strong evidence for cosmic ray acceleration beyond PeV energies within the Milky Way.
- * Diffuse gamma-ray emission is a key indicator of Galactic cosmic ray distribution and acceleration.
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