Vol 12, No 11

A survey of CO and its isotope lines for possible cloud-cloud collision candidates

Nan Li, Jun-Jie Wang


Abstract In the 12CO (J=1–0) survey of 1331 cold IRAS sources, 214 sources show profiles with multiple peaks and are selected as cloud-cloud collision candidates. In January 2005, 201 sources were detected with 12CO(1–0), 13CO(1–0), and C18O(1–0) emissions by the 13.7 m telescope at Purple Mount Observatory. This is the first survey of CO and its isotope lines directed toward possible cloud-cloud collision regions. According to the statistics of the 201 sources in the 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 Galactocentric distances, and are partly associated with the star forming region. Based on preliminary criteria which describe the spectral 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 possible cloud-cloud collision regions, and gives some evidence to help us with selecting the target region. We will continue the process of mapping and studying multi-wavelength observations for the selected region in the future.


Keywords stars: formation — ISM: clouds — ISM: molecules

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