Constraining Cosmic Ray Origins Through Spectral Radio Breaks In Supernova Remnants
Abstract
Supernova remnants (SNRs) have long been hypothesized to accelerate Galactic cosmic rays. The energy of accelerated protons can be measured if gamma-ray emission arises primarily from inelastic collisions with the surrounding gas through neutral pion decay. Here, we constrain the accelerated particle spectrum of both electrons and protons through modeling the non-thermal emission from radio to gamma rays. We analyze the synchrotron radiation spectrum of four bright radio sources detected by the Fermi Gamma-Ray Space Telescope: IC443, HB21, Cygnus Loop, and Puppis A. WMAP and Planck data were used to extend the radio spectrum to millimeter wavelengths to constrain the spectrum of relativistic electrons. We detect spectral breaks for SNRs: HB 21, IC443 and Puppis A. This complements the possible spectral breaks previously reported for WMAP data, and is consistent with spectral breaks found in the Planck collaboration microwave survey of SNRs. The presence of a break in the radio synchrotron spectrum for Puppis A is inconsistent with leptonic models of gamma-ray emission. In Cygnus Loop, the lack of a break is only consistent with hadronic models.
- Publication:
-
American Astronomical Society Meeting Abstracts #225
- Pub Date:
- January 2015
- Bibcode:
- 2015AAS...22514018R