Very recently, the Tibet-ASγ collaboration reported the detection of γ rays from the galactic disk in the energy range of 100 TeV -- 1 PeV. Remarkably, many of these γ rays were observed apart from known very high energy (E> 100 GeV) γ-ray sources. These results are best understood if these diffuse γ rays: 1) were produced by a conventional rather than an exotic (i.e. dark matter decay or annihilation) process, 2) have a hadronic rather than a leptonic origin, 3) were produced in impulsive rather than stable sources or, alternatively, in optically thick sources. In addition to that, the detection of the sub-PeV diffuse γ rays implies a limit on the flux of neutrinos from the Galactic disk and a lower limit on the rigidity of the cutoff in the Galactic cosmic ray spectrum.
@article{arxiv.2104.02838,
title = {Implications of the detection of sub-PeV diffuse $\gamma$ rays from the Galactic disk apart from discrete sources},
author = {Timur Dzhatdoev},
journal= {arXiv preprint arXiv:2104.02838},
year = {2021}
}