9–13 déc. 2024
Paris
Fuseau horaire Europe/Paris

Energy dependence of the knee in the cosmic-ray spectrum across the Milky Way

Non programmé
20m
APC Laboratory (Paris)

APC Laboratory

Paris

Amphithéâtre Pierre-Gilles de Gennes (floor -1), 10 rue Alice Domon et Leonid Duquet, 75013 Paris

Description

The all-particle spectrum of cosmic rays measured at Earth has a knee-like feature around 4 PeV. A priori, it is not clear if this is a local feature specific to the Solar neighbourhood in the Milky Way, or if it is a generic property of the Galactic cosmic-ray spectrum. We argue that combining gamma-ray and cosmic-ray data of LHAASO indicates that the knee is a local feature. In order to demonstrate this, we derive a model for the local cosmic-ray spectrum and composition, consistent with the recent LHAASO measurements of the all-particle spectrum and the mean logarithmic mass in the knee region. We calculate the spectrum of diffuse gamma-ray emission based on this model and find that the expected spectral shape of the diffuse gamma-ray flux disagrees with the LHAASO measurements of the diffuse gamma-ray emission in the 10-100 TeV energy range in the inner and outer Galaxy. We determine the break energy in the CR spectrum expected from these gamma-ray data and find it an energy ten times lower than obtained from local measurements.

Affiliation IAP (Sorbonne University and CNRS)

Auteur principal

Co-auteurs

Andrii Neronov Dmitri SEMIKOZ (APC, Paris) Michael Kachelriess (Department of Physics, NTNU) M. Sergey Koldobskiy (Sodankyl¨a Geophysical Observatory and Space Physics and Astronomy)

Documents de présentation

Aucun document.