Galactic gamma-ray and neutrino emission from interacting cosmic-ray nuclei
Abstract
We present a study of the expectations for very-high-energy (VHE) to ultra-high-energy (UHE) gamma-ray and neutrino emission from interacting cosmic rays in our Galaxy as well as a comparison to the latest results for the Galactic UHE diffuse emission. We demonstrate the importance of properly accounting for both the mixed cosmic-ray composition and the gamma-ray absorption. We adopt the wounded-nucleon model of nucleus interactions and provide parameterisations of the resulting gamma-ray and neutrino production. Nucleon shielding due to clustering inside nuclei is shown to have a measurable effect on the production of gamma rays and is particularly evident close to breaks and cutoffs in mixed-composition particle spectra. The change in composition around the `knee' in the cosmic ray spectrum has a noticeable impact on the diffuse neutrino and gamma-ray emission spectra. We show that current and near-future detectors can probe these differences in the key energy range from 10 TeV to 1 PeV, testing the paradigm of the universality of the cosmic ray spectrum and composition throughout the Galaxy.
- Publication:
-
Astronomy and Astrophysics
- Pub Date:
- May 2022
- DOI:
- 10.1051/0004-6361/202141318
- arXiv:
- arXiv:2201.03984
- Bibcode:
- 2022A&A...661A..72B
- Keywords:
-
- radiation mechanisms: non-thermal;
- cosmic rays;
- neutrinos;
- gamma rays: ISM;
- Astrophysics - High Energy Astrophysical Phenomena
- E-Print:
- 17 pages, 12 figures, accepted for publication by A&