A NEW LOOK at the INTEGRATED RADIO/MICROWAVE CONTINUUM SPECTRUM of GALACTIC SUPERNOVA REMNANT IC 443

Abstract

Recent observations of the microwave sky, by space telescopes such as the Wilkinson Microwave Anisotropy Probe and Planck, have opened a new window into the analysis of continuum emission from supernova remnants (SNRs). In this paper, different emission models that can explain the characteristic shape of currently known integrated radio/microwave continuum spectrum of the Galactic SNR IC 443 are tested and discussed. In particular, the possibility is emphasized that the slight bump in the integrated continuum of this remnant around 20-70 GHz is genuine and that it can be explained by the contribution of an additional emission mechanism such as spinning dust. We find that adding a spinning dust component to the emission model improves the fit of the integrated spectrum of this SNR while at the same time preserving the physically probable parameter values. Finally, models that include the high-frequency synchrotron bending of the IC 443 radio to microwave continuum are favored.