Molecular clouds near supernova remnants

Observations of the interactions of molecular clouds with supernova remnants, which may lead to cloud collapse, are presented. A survey of 14 SNRs was performed in the 4.8-GHz absorption line of H2CO with the Effelsberg 100-m radio telescope to obtain spectral line maps capable of indicating interactions with molecular clouds. Two of the SNRs surveyed, W28 and W44, are found to possibly interact with neighboring molecular clouds based on their geometries, radial velocities and line width variations. Results suggest that a portion of the molecular clouds was accelerated by the SNR expansion to a velocity of about 5 km/sec, with its velocity dispersion, temperature and density left unchanged.