A new look at the integrated radio/microwave continuum spectrum of Galactic supernova remnant IC443

TL;DR

This paper analyzes the radio/microwave spectrum of the Galactic supernova remnant IC 443, proposing that a spinning dust component explains observed spectral features and improves model fits.

Contribution

It introduces a model including spinning dust emission to better explain IC 443's spectrum, highlighting the significance of this component in supernova remnant analysis.

Findings

Adding spinning dust improves spectral fit

High-frequency synchrotron bending models are favored

Spinning dust accounts for the 20-70 GHz bump

Abstract

Recent observations of the microwave sky, by the space telescopes such as WMAP 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 presently known integrated radio/microwave continuum spectrum of the Galactic SNR IC 443 are tested and discussed. In particular, the possibility that the slight bump in the integrated continuum of this remnant around 20 -- 70~GHz is genuine and that can be explained by the contribution of additional emission mechanism such as of spinning dust is emphasized. 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 preserves the physically probable parameter values. Finally, models that include the high-frequency synchrotron bending of the IC 443 radio to microwave continuum are favored.