Radioactivity and Electron Acceleration in Supernova Remnants

TL;DR

This paper proposes that radioactive decay in supernova remnants supplies electrons and positrons that are further accelerated by shocks, potentially solving the electron injection problem in these environments.

Contribution

It introduces a novel link between radioactive decay and particle acceleration, suggesting decay products as a source of energetic electrons in supernova remnants.

Findings

Radioactive decay can supply enough energetic electrons and positrons for supernova remnant observations.

Stochastic pre-acceleration in shock regions is necessary for these particles to match observational data.

The model explains electron injection in the supernova remnant Cas A.

Abstract

We argue that the decays of radioactive nuclei related to $^{44}$Ti and $^{56}$Ni ejected during supernova explosions can provide a vast pool of mildly relativistic positrons and electrons which are further accelerated to ultrarelativistic energies by reverse and forward shocks. This interesting link between two independent processes - the radioactivity and the particle acceleration - can be a clue for solution of the well known theoretical problem of electron injection in supernova remnants. In the case of the brightest radio source Cas A, we demonstrate that the radioactivity can supply adequate number of energetic electrons and positrons for interpretation of observational data provided that they are stochastically pre-accelerated in the upstream regions of the forward and reverse shocks.