A survey of CO and its isotope lines for possible cloud-cloud collision
  candidates
  In the 12CO (J=1-0) survey for the 1331 cold IRAS sources 214 sources show
profiles with multiple-peak profiles and are selected as cloud-cloud collision
candidates. In January 2005, 201 sources are detected with 12CO(1-0),
13CO(1-0), and C18O(1-0) emission by the 13.7m telescope at Purple Mount
Observatory. This is the first CO and its isotope lines directed toward
possible cloud-cloud collision regions. According to the statistics of the 201
sources in Galactic distribution, the 201 sources show a similar distribution
to the parent sample (1331 cold IRAS sources). These sources are located over a
wide range of the Galactocentric distances, and are partly associated with the
star formation region. Based on preliminary criteria which describe the
spectrum properties of the possible cloud-cloud collision region, the 201
sources are classified into four types by the fit of the spectral profiles
between the optically thick and thin lines toward each source. The survey is
focused on the possible cloud-cloud collision regions, and gives some evidences
to help us with selecting the target region. Then we will carry on the mapping
and multi-wavelength study for the selected region in future.
