On the e$^+$e$^-$ excesses and the knee of the cosmic ray spectra -- hints of cosmic rays acceleration at young supernova remnants

TL;DR

This paper proposes that features like the cosmic ray knee and electron/positron excesses can be explained by interactions in young supernova remnants, supporting their role in cosmic ray acceleration.

Contribution

It introduces a unified model linking cosmic ray spectral features to pair production in young supernova remnants, providing evidence for their role in cosmic ray acceleration.

Findings

Reproduces spectral features with numerical calculations

Supports supernova remnants as cosmic ray sources

Links electron/positron excesses to supernova interactions

Abstract

Supernova remnants have long been regarded as sources of the Galactic cosmic rays up to petaelectronvolts, but convincing evidence is still lacking. In this work we explore the common origin of the subtle features of the cosmic ray spectra, such as the knee of cosmic ray spectra and the excesses of electron/positron fluxes recently observed by ATIC, H.E.S.S., Fermi-LAT and PAMELA. Numerical calculation shows that those features of cosmic ray spectra can be well reproduced in a scenario with e$^+$e$^-$ pair production by interactions between high energy cosmic rays and background photons in an environment similar to the young supernova remnant. The success of such a coherent explanation serves in turn as an evidence that at least a portion of cosmic rays might be accelerated at young supernova remnants.