HCN Emission in the Sagittarius A Molecular Cloud
Abstract
The molecular clould near Sagittarius A has been mapped in the J=1-0 emission line of hydrogen cyanide (H12CN) with a 2'-grid using the 6-m millimeter-wave telescope of the Tokyo Astronomical Observatory. The full extent of the molecular cloud was found to be about 26' x 8' in galactic longitude and latitude, respectively, and its total mass was estimated to be 3 x 106 M . The brightest part of the cloud defines a thin straight ridge. The molecular cloud shows an apparent anticorrelation to the distribution of radio continuum radiation, but resembles rather well the far- and near-infrared distributions. The velocity field of the cloud is complex and is not dominated by any monotonic velocity gradient. H18CN (1-0) emission was observed at one position. Other molecules (HCO+, HC3N, SO2, and H2CO) were also observed in the 3 to 4-mm region at the peak positions of H12CN. Based upon these results, the origin and the structure of the cloud are discussed in terms of mass ejection from the nucleus. Key words: Activities in the galactic nucleus; Interstellar molecules; Sagittarius A; The galactic center.
- Publication:
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Publications of the Astronomical Society of Japan
- Pub Date:
- 1977
- Bibcode:
- 1977PASJ...29..643F