TeV spectral bump of cosmic-ray protons and helium nuclei: the role of nearby supernova remnants

TL;DR

This paper explains the TeV spectral bump in cosmic-ray protons and helium nuclei as resulting from nearby supernova remnants, especially Vela, using an improved analysis and updated remnant data.

Contribution

It provides a detailed analysis showing that nearby supernova remnants can account for the spectral bump and aligns with observed spectra of heavier cosmic rays and the all-particle spectrum.

Findings

Spectral bump explained by nearby supernova remnants, especially Vela.

Contribution from remnants matches observed cosmic-ray spectra.

Combined model fits data beyond the knee region.

Abstract

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