A Study of the Molecular Cloud toward the H {II} Regions S35 and S37 with NANTEN
Abstract
We have made new observations of a large field of ~ 10 square degrees toward the two southern H {II} regions S35 and S37. Observations were made in the 12CO, 13CO, and C18O J=1 - 0 emission with the NANTEN telescope at Las Campanas, Chile. These observations have revealed a giant molecular cloud of ~ 1.3 times 105 MO in 12CO , highly elongated with a size of ~ 80 pc times ~ 20 pc, where a previously known active site of star formations, including GGD 27IR and HH 80/81, is located. The cloud appears lifted up to z ~ 100 pc from the galactic plane at an inclination angle of ~ 70deg, exhibiting indications of strong interactions with the H {II} regions. Star formation has been found to be very active in the cloud. We have discovered four molecular outflows driven by luminous far-infrared sources of ~ 102 - 104LO in addition to that previously known toward GGD 27IR. The activity is also demonstrated by the existence of several dense C18O clumps whose mass ranges from ~ 3 x 102 MO to ~ 4 x 103 MO . The five molecular outflows are embedded in these C18O clumps. In addition, a comparison with H {I} shows that the CO cloud is located at the edge of an H {I} hole of ~ 55 pc radius. Since the H {I} gas surrounding the hole shows a signature of expansion at several km s-1, we suggest that the H {I} hole represents a supershell created by some explosive events, like supernova explosions, during the last ~ 4 x 106 yr. This supershell may also provide an explanation for the origin of the molecular distribution.
- Publication:
-
Publications of the Astronomical Society of Japan
- Pub Date:
- December 1999
- DOI:
- 10.1093/pasj/51.6.819
- Bibcode:
- 1999PASJ...51..819S
- Keywords:
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- ISM: CLOUDS;
- ISM: MOLECULES;
- ISM: H {II} REGIONS;
- STARS: FORMATION