Galactic diffuse gamma rays meet the PeV frontier

Abstract

The Tibet AS$\gamma$ and LHAASO collaborations recently reported the observation of a $\gamma$-ray diffuse emission with energy up to the PeV from the Galactic plane. We discuss the relevance of non-uniform cosmic-ray transport scenarios and the implications of these results for cosmic-ray physics. We use the {\tt DRAGON} and {\tt HERMES} codes to build high-resolution maps and spectral distributions of that emission for several representative models under the condition that they reproduce a wide set of local cosmic-ray data up to 100 PeV. We show that the energy spectra measured by Tibet AS$\gamma$, LHAASO, ARGO-YBJ and Fermi-LAT in several regions of interest in the sky can all be consistently described in terms of the emission arising by the Galactic cosmic-ray "sea". We also show that all our models are compatible with IceTop $\gamma$-ray upper limits. Our results favor transport models characterized by spatial-dependent diffusion although some degeneracy remains between the choice of the transport scenario and that of the cosmic-ray spectral shape above 10 TeV. We discuss the role of forthcoming measurements in resolving that ambiguity.

10 pages, 9 figures, 1 table, material provided through https://github.com/tospines/Gamma-variable_High-resolution

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Cited by in corpus (25)

• Measurement of ultra-high-energy diffuse gamma-ray emission of the Galactic plane from 10 TeV to 1 PeV with LHAASO-KM2A
• Diffuse Emission of Galactic High-Energy Neutrinos from a Global Fit of Cosmic Rays
• Galactic diffuse gamma-ray emission from GeV to PeV energies in light of up-to-date cosmic ray measurements
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• Prospects for a survey of the Galactic plane with the Cherenkov Telescope Array
• Starburst Nuclei as Light Dark Matter Laboratories
• Possible contribution of X-ray binary jets to the Galactic cosmic ray and neutrino flux
• Multi-TeV dark matter density in the inner Milky Way halo: spectral and dynamical constraints
• Prospects for $\gamma$-ray observations of the Perseus galaxy cluster with the Cherenkov Telescope Array
• Cosmic Ray Feedback on Bi-stable ISM Turbulence
• The Origin of the Very-High-Energy Diffuse $\gamma$-Ray Emission: The Case for Galactic Source Cocoons
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• Cosmic-Ray Mass Composition around the Knee via Principal Component Analysis
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