Young Supernova Remnants and the Knee in the Cosmic Ray Sectrum

TL;DR

This paper explores how young supernova remnants and associated neutron stars could be the sources of PeV cosmic rays and explain the knee in the cosmic ray spectrum, but only under rare, specific conditions.

Contribution

It proposes a model linking neutron stars in young supernova remnants to the cosmic ray knee and positron fluxes, emphasizing the rarity of suitable supernova events.

Findings

Neutron stars in young SNRs can produce PeV cosmic rays.

The cosmic ray knee may result from interactions in specific supernova environments.

Rare, recent supernovae are likely responsible for observed phenomena.

Abstract

It has recently been suggested that neutron stars inside the shells of young supernova remnants (SNR) are the sources of PeV cosmic rays and that the interaction of the particles with the radiation field in the SNR causes electron pair production, which has relevance to recent observations of 'high' positron fluxes. Furthermore, the character of the interaction is such that the well-known knee in the cosmic ray energy spectrum can be explained. Our examination of the mechanism leads us to believe that the required parameters of SN and pulses are so uncommon that the knee and positron fraction can only be explained if a single, local and recent SN - and associated pulsar - are concerned.