SIMBAD references

Observations at 1420 and 408 MHz were made with the Dominion Radio Astrophysical Observatory Synthesis Telescope of the region including IC 443 and G189.6+3.3. A spectral index map is computed: the bright northeast part of IC 443 has 408-1420 MHz spectral index α=0.43±0.02, the southwest part has α=0.2-0.6, and G189.6+3.3 has α=0.1-0.7. The radio images are compared with optical, infrared, molecular line, and X-ray images. The appearance of IC 443 as two half-shells is due to the ring of shocked molecular gas that sits at the join of the half-shells. G189.6+3.3 has nonthermal radio emission and is confirmed as a separate supernova remnant. The pulsar wind nebula found by Chandra likely originates in G189.6+3.3 rather than in IC 443.