Planck intermediate results. XXXI. Microwave survey of Galactic supernova remnants
Abstract
The all-sky Planck survey in 9 frequency bands was used to search for emission from all 274 known Galactic supernova remnants. Of these, 16 were detected in at least two Planck frequencies. The radio-through-microwave spectral energy distributions were compiled to determine the mechanism for microwave emission. In only one case, IC 443, is there high-frequency emission clearly from dust associated with the supernova remnant. In all cases, the low-frequency emission is from synchrotron radiation. As predicted for a population of relativistic particles with energy distribution that extends continuously to high energies, a single power law is evident for many sources, including the Crab and PKS 1209-51/52. A decrease in flux density relative to the extrapolation of radio emission is evident in several sources. Their spectral energy distributions can be approximated as broken power laws, Sν ∝ ν-α, with the spectral index, α, increasing by 0.5-1 above a break frequency in the range 10-60 GHz. The break could be due to synchrotron losses.
- Publication:
-
Astronomy and Astrophysics
- Pub Date:
- February 2016
- DOI:
- 10.1051/0004-6361/201425022
- arXiv:
- arXiv:1409.5746
- Bibcode:
- 2016A&A...586A.134P
- Keywords:
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- ISM: supernova remnants;
- cosmic rays;
- radio continuum: ISM;
- Astrophysics - Astrophysics of Galaxies
- E-Print:
- A&