Models of molecular cloud cores II: Multi-transition study of C(34)S.

The dense cores embedded in the M17, S140, and NGC 2024 molecular clouds have been mapped in the J=5->4, J=3->2, and J=2->1 transitions of C(34)S. The C(34)S lines are, on the average, a factor of 3-4 weaker and 25% narrower than the CS lines mapped in the same cores by Snell et al. (1984). The data for the three transitions of C(34)S have been fitted to spherical LVG models for the excitation to derive estimates of the gas density and C(34)S column density at each observed position. Most of the data are well fitted by these simple models.