Welcome to the new version of CaltechAUTHORS. Login is currently restricted to library staff. If you notice any issues, please email coda@library.caltech.edu
Published October 15, 1975 | Published
Journal Article Open

The molecular cloud Sagittarius B2


The structure of the Sgr B2 molecular cloud has been studied by detailed and extensive mappings of the CO, ^(13)CO, CS, and H_2CO (2-cm) transitions. The cloud consists of a dense core at the OH maser position plus a very large envelope 45 pc across. Sagittarius B2 is one of the most massive objects in the Galaxy, containing about 3 x 10^6 M_⊙ - an estimate arrived at independently from calculated ^(13)CO column densities, from application of the virial theorem, and from far-infrared measurements. The molecular gas has an average temperature T_k of ~ 20 K; that this is similar to the temperature of grains emitting far-infrared radiation is taken as evidence of near thermal equilibrium between dust grains and H_2. The dynamics of the gas in the cloud is found to be dominated by large-scale systematic motions with velocity not a monotonic function of radius.

Additional Information

© 1975. The American Astronomical Society. Received 1975 February 19; revised 1975 April 17. We are grateful to Peter Wannier for his aid in obtaining some of the spectra used in Figure 2 and to John Kwan, Peter Goldreich, Mark Morris, and Dan Gezari for suggestions upon an earlier draft and to Claudine Gignoux for help in data reduction. This research is sponsored in part by a National Science Foundation grant GP-30400-X5 and by the Office of Naval Research under contract N0014-67-A-0094-0019 at the Owens Valley Radio Observatory.

Attached Files

Published - 1975ApJ___201__352S.pdf


Files (1.3 MB)
Name Size Download all
1.3 MB Preview Download

Additional details

August 19, 2023
October 20, 2023