Astronomy and Astrophysics – Astronomy
Scientific paper
Jan 1993
adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=1993phdt........69s&link_type=abstract
PhD Dissertation, Massachusetts Inst. of Tech. Cambridge, MA United States
Astronomy and Astrophysics
Astronomy
Transition, Galactic Nuclei, Molecular Spectra, Spectrum Analysis, Galactic Radiation, Line Spectra, Molecular Clouds, Very Large Array (Vla), Radio Astronomy, Methyl Alcohol, Ammonia, Cyanides, Morphology
Scientific paper
A multi-spectral line, multi-resolution, observational study has been conducted toward the Galactic center region. Specifically, observations have been made in the 4-1 to 340 E transition of methanol using the Haystack 37 m telescope, in the (J,K) = (3,3) inversion transition of ammonia using the Effelsberg 100 m telescope and the NRAO Very Large Array (VLA), and in the J = 1 to 0 and J = 3 to 2 transitions of hydrogen cyanide using the IRAM 30 m telescope and the CSO 10 m telescope, respectively. Most of the region within a radius of approximately 10 pc of Sgr A* has been mapped with at least full-beam sampling. The two GMCs in the mapped region, M-0:02 - 0.07 (the 50 km/s cloud) and M-0.13 - 0.08 (the 20 km/s cloud), exhibit very similar physical characteristics, including size (approximately 4 x 5 pc) and mass (approximately 104 - 105M(solar mass)). Class 1 methanol maser emission provides evidence for shock interaction between the Sgr A-East shell source and M-0.02 - 0.07. Additional maser emission is detected in the region approximately 3' south of Sgr A*, where an SNR proposed by Ho et al. (1985), may impact on M-0.13 - 0.08. The velocity signature of a red-shifted expanding shell, seen in the ammonia inversion line, indicates that the Sgr A-East shell source is impacting on the 50 km/s cloud to the rear along the line-of-sight and that the cloud is located at about its projected distance from the central region. Morphological evidence for an extension, or streamer, from each molecular cloud is seen in each transition observed. One streamer extends northward in projection from the 20 km/s cloud, while another streamer extends westward in projection from the 50 km/s cloud. The morphological connection of the GMCs to the central region is most strongly indicated by the HCN transitions. Supernova impact may loosen material from the molecular clouds which is then captured by the central gravitational potential. Tidal forces may then stretch the infalling material into streamers. If correct, this is the first example of the feeding of molecular material toward the center of a galaxy where the morphology and kinematics can be studied in detail.
No associations
LandOfFree
Gas feeding of the Galactic center region does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with Gas feeding of the Galactic center region, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Gas feeding of the Galactic center region will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-1264590