Cosmic Ray Electron Evolution in Supernova Remnants: Log-Parabola Distribution

TL;DR

This paper models electron acceleration in supernova remnants using a log-parabola distribution, successfully reproducing observed spectra and analyzing the effects of energy-dependent escape and parameter sensitivity.

Contribution

It introduces a model of electron escape at SNR shock fronts that explains observed spectral features with a log-parabola distribution and examines parameter sensitivities.

Findings

Model reproduces spectra of RX J1713.7-3946 and SN 1006.

Electron-escape energy dependence is weak but spectra are sensitive to escape parameters.

Electron and photon spectra evolve with SNR evolution and energy losses.

Abstract

The shock fronts of supernova remnants (SNRs) are believed to be significant sites of acceleration of cosmic ray particles. Previous researchers have shown that a particle distribution similar to a log-parabola can be generated when particles have an energy-dependent escape. We explore the acceleration of electrons at SNR shock fronts, and show that modeling this energy-dependent particle escape model can produce spectral energy distributions consistent with observations of two lepton-radiation-dominated SNRs: RX J1713.7-3946 and SN 1006. The model includes the evolution of both the electron distribution and photon spectra as a result of the combined effects of the SNR evolution and electron energy loss. The electron-escape energy dependence is quite weak, but the electron distribution and photon spectra turn out to be very sensitive to changes in the electron escape. We also explore how sensitive the spectra and electron distributions are to the parameters used in the log-parabola model.