The TeV Spectral Bump of Cosmic-Ray Protons and Helium Nuclei: The Role of Nearby Supernova Remnants

Abstract

The existence of nearby discrete cosmic-ray (CR) sources can lead to many interesting effects on the observed properties of CRs. Recent measurements of CRs with the CALET and the DAMPE experiments have revealed a bump-like new feature in the proton and helium spectra in the energy range ∼(1–100) TeV n−1. The origin of the feature is not clearly understood. In this paper, considering an improved and more detailed analysis than previous works, and using updated age and distance estimates of nearby supernova remnants (SNRs) along with an energy-dependent escape process for CRs from the remnants, we show that the spectral bump can be explained by the contribution of CRs from the nearby SNRs, in particular the Vela remnant. We also show that the contribution from the nearby remnants agrees well with the observed spectra of the heavier CR elements from carbon to iron, as well as with the measured all-particle CR spectrum beyond the knee region when combined with a background flux of CRs originating from distant SNRs.