Discovery of shocked CO within a supernova remnant

Abstract

Shocked CO is seen within the supernova remnant IC 443, in association with the accelerated H I and OH clouds. The CO lines have velocity widths of 20 km/s and appear to be optically thin. CO column densities in the shocked gas, 10 to the 16th per sq cm, are similar to those measured in the preshock cloud. The ratio of ground-state OH/CO column densities is enhanced by two orders of magnitude in one shocked region, as compared with the preshock cloud.