TY  - JOUR
AU  - De La Torre Luque, P.
AU  - Gaggero, D.
AU  - Grasso, D.
AU  - Fornieri, O.
AU  - Egberts, K.
AU  - Steppa, C.
AU  - Evoli, C.
PY  - 2023
DA  - 2023//
TI  - Galactic diffuse gamma rays meet the PeV frontier
T2  - Astron. Astrophys.
JO  - Astronomy & Astrophysics
SP  - A58 - 11pp
VL  - 672
PB  - Edp Sciences S A
KW  - diffusion
KW  - cosmic rays
KW  - Galaxy
KW  - general
KW  - gamma rays
KW  - diffuse background
AB  - The Tibet AS gamma and LHAASO collaborations recently reported the observation of a gamma-ray diffuse emission with energy up to the PeV level from the Galactic plane.Aims. We discuss the relevance of non-uniform cosmic-ray transport scenarios and the implications of these results for cosmic-ray physics.Methods. We used the DRAGON and 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.Results. 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 reasonably 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.Conclusions. We compare the predictions of conventional and space-dependent transport models with those data sets. Although the Fermi-LAT, ARGO-YBJ, and LHAASO preliminary data slightly favor this scenario, due to the still large experimental errors, the poorly known source spectral shape at the highest energies, the potential role of spatial fluctuations in the leptonic component, and a possible larger-than-expected contamination due to unresolved sources, a solid confirmation requires further investigations. We discuss which measurements will be most relevant in order to resolve the remaining degeneracy.
SN  - 0004-6361
UR  - https://arxiv.org/abs/2203.15759
UR  - https://doi.org/10.1051/0004-6361/202243714
DO  - 10.1051/0004-6361/202243714
LA  - English
N1  - WOS:000960963900005
ID  - DeLaTorreLuque_etal2023
ER  -