Studies of dense molecular cores in regions of massive star formation. IV. Multitransition CS-study towards^*

Helsinki University Observatory, Tähtitorninmäki, P.O. Box 14, SF-00014 University of Helsinki, Finland

Received: 25 September 1995
Accepted: 19 December 1995

Abstract

We have observed CS and C³⁴S emission towards 33 H₂O maser positions in the southern sky () using the SEST telescope. Most of the sources were selected also for their association with strong IRAS sources. CS(2-1) was detected in all sources, with the possible exception of two. Most sources were also mapped in the transitions CS(5-4) and C³⁴S(2-1) and half of the sample also in CS(2-1). CS and C³⁴S transitions were measured towards the centres of the clouds as determined from the mapping. CS and C³⁴S transitions were measured in about a half dozen clouds. CO(1-0) was measured in most clouds in order to determine the kinetic temperatures. The CS column densities were calculated using the LTE approximation. All measurements were also analyzed using a spherical LVG model. We present the observational data and the results of this analysis.