J = 4-3 HCN observations of M17 SW, DR 21/OH/, W51 and NGC 6334

White, G. J.; Phillips, J. P.; Beckman, J. E.; Cronin, N. J.
Bibliographical reference

Monthly Notices of the Royal Astronomical Society, vol. 199, Apr. 1982, p. 375-383. Research supported by the Science Research Council.

Advertised on:
4
1982
Number of authors
4
IAC number of authors
0
Citations
14
Refereed citations
14
Description
We report observations of NGC 6334N, Ml7 5W, W 51 and DR2l(OH) in the J = 4→3 transition of HCN at 354GHz. These results are combined with previously obtained J=1→0HCN data to determine molecular abundances X(HCN) ˜4 × 10-11 -4 × 10-12, and characteristic line excitation zone densities n(H2)˜106 cm-3. These results are at variance with previous analyses based on J=1→0 results alone, and the predictions of certain models of the cloud chemistry. The reasons for these discrepancies are discussed.