On cosmic ray acceleration in supernova remnants and the FERMI/PAMELA data

TL;DR

This paper investigates how supernova remnants can accelerate cosmic rays and produce high-energy positrons and electrons, explaining recent observations by PAMELA and Fermi, and predicts detectable neutrino fluxes.

Contribution

It demonstrates that diffusive shock acceleration in supernova remnants can account for the rising positron fraction and fits the observed electron-positron spectrum using galactic SNR distribution models.

Findings

Diffusive shock acceleration can explain the positron excess observed by PAMELA.

The model fits the Fermi electron-positron spectrum.

IceCube may detect neutrinos from nearby supernova remnants.

Abstract

We discuss recent observations of high energy cosmic ray positrons and electrons in the context of hadronic interactions in supernova remnants, the suspected accelerators of galactic cosmic rays. Diffusive shock acceleration can harden the energy spectrum of secondary positrons relative to that of the primary protons (and electrons) and thus explain the rise in the positron fraction observed by PAMELA above 10 GeV. We normalize the hadronic interaction rate by holding pion decay to be responsible for the gamma-rays detected by HESS from some SNRs. By simulating the spatial and temporal distribution of SNRs in the Galaxy according to their known statistics, we are able to then fit the electron (plus positron) energy spectrum measured by Fermi. It appears that IceCube has good prospects for detecting the hadronic neutrino fluxes expected from nearby SNRs.