Non-thermal bremsstrahlung from supernova remnants and the effect of Coulomb losses

Abstract

I investigate the shape of the electron cosmic ray spectrum in the range up to ~1000 keV, assuming that the acceleration process at the shock results in a power law in momentum, and that downstream of the shock the spectrum is affected by Coulomb interactions with background electrons only. In the non-relativistic regime one can analytically determine the energy of an electron starting with a certain energy, and use this result to produce an electron cosmic ray spectrum, modified by Coulomb losses. An analytic expression for the electron spectrum is obtained that depends on the parameter n_e t, which can be estimated from a similar parameter used to characterize the line spectra of supernova remnants. For the brightest supernova remnants n_e t > 1e11 cm^-3 s,and most of the electrons accelerated to < 100 keV have lost their energy. Because of its high radio flux, Cas A is the most likely candidate for non-thermal bremsstrahlung. Although it has n_e t ~ 2e11 cm^-3 s, one may expect to pick up non-thermal bremsstrahlung above 100 keV with current hard X-ray detectors.

To be published as a research note in A & A

References in corpus (6)

• Observational constraints on energetic particle diffusion in young SNRs: amplified magnetic field and maximum energy
• A Physical Relationship Between Electron-Proton Temperature Equilibration and Mach Number in Fast Collisionless Shocks
• Confirmation of strong magnetic field amplification and nuclear cosmic ray acceleration in SN 1006
• The signature of 44Ti in Cassiopeia A revealed by IBIS/ISGRI on INTEGRAL
• Cosmic ray diffusion near the Bohm limit in the Cassiopeia A supernova remnant
• X-Ray Observations of SN 1006 with Integral

Cited by in corpus (10)

• Characterizing the non-thermal emission of Cas A
• Locating the most energetic electrons in Cassiopeia A
• The Hard X-Ray View of the Young Supernova Remnant G1.9+0.3
• Suppression of Bremsstrahlung losses from relativistic plasma with energy cutoff
• LMC N132D: A mature supernova remnant with a power-law gamma-ray spectrum extending beyond 8 TeV
• An XMM-Newton Study of the Mixed-Morphology Supernova Remnant G346.6-0.2
• Evidence for thermal X-ray emission from the synchrotron dominated shocks in Tycho's supernova remnant
• The auto and cross angular power spectrum of the Cas A supernova remnant in radio and X-ray
• Nonthermal processes and particle acceleration in supernova remnants
• The forward and reverse shock dynamics of Cassiopeia A