Cosmic ray electrons and positrons from supernova explosions of massive stars

TL;DR

This paper proposes that cosmic ray electrons and positrons originate from supernova shocks in the polar caps of massive stars, explaining observed excesses and spectral features through magnetic field geometry effects.

Contribution

It introduces a novel model linking cosmic ray excesses to supernova shock acceleration in stellar polar caps, with specific spectral predictions.

Findings

Explains cosmic ray excesses via polar cap acceleration.

Predicts a source spectrum of E^-2 steepened to E^-3 in observations.

Forecasts an E^-4 cutoff in the cosmic ray spectrum.

Abstract

We attribute the recently discovered cosmic ray electron and cosmic ray positron excess components and their cutoffs to the acceleration in the supernova shock in the polar cap of exploding Wolf Rayet and Red Super Giant stars. Considering a spherical surface at some radius around such a star, the magnetic field is radial in the polar cap as opposed to most of 4 pi (the full solid angle), where the magnetic field is nearly tangential. This difference yields a flatter spectrum, and also an enhanced positron injection for the cosmic rays accelerated in the polar cap. This reasoning naturally explains the observations. Precise spectral measurements will be the test, as this predicts a simple E^-2 spectrum for the new components in the source, steepened to E^-3 in observations with an E^-4 cutoff.