ISM Processing in the Inner 20 pc in Galactic center

Abstract

We present the Submillimeter Array (SMA) 157-pointing mosaic in 0.86 mm dust continuum emission with 5$".1\times 4"$.2 angular resolution, and the NRAO Green Bank 100m Telescope (GBT) observations of the CS/C${}^{34}$S/${}^{13}$CS 1-0 and SiO 1-0 emission with $\le 20"$$\times 18"$ angular resolution. The dust continuum image marginally resolves at least several tens of 10-10${}^2$ $M_{\odot }$ dense clumps in the 5${}^{\prime }$ field including the circumnuclear disk (CND) and the exterior gas streamers. There is very good agreement between the high resolution dust continuum map of the CND and all previous molecular line observations. As the dust emission is the most reliable optically thin tracer of the mass, free from most chemical and excitation effects, we demonstrate the reality of the abundant localized structures within the CND, and their connection to external gas structures. From the spectral line data, the velocity dispersions of the dense clumps and their parent molecular clouds are $\sim$10-20 times higher than their virial velocity dispersions. This supports the idea that the CND and its immediate environment may not be stationary or stable structures. Some of the dense gas clumps are associated with 22 GHz water masers and 36.2 GHz and 44.1 GHz CH${}_3$OH masers. However, we do not find clumps which are bound by the gravity of the enclosed molecular gas. Hence, the CH${}_3$OH or H${}_2$O maser emission may be due to strong (proto)stellar feedback, which may be dispersing some of the gas clumps.

7 pages, 15 figures; Accepted by ApJ

References in corpus (6)

• The SCUBA Legacy Catalogue: Continuum Objects Detected by SCUBA
• Dynamics of Ionized Gas at the Galactic Center: VLA Observations of the 3D Velocity Field and Location of the Ionized Streams in Sagittarius A West
• A Large Scale Survey of NGC1333
• Massive Star Formation in the Molecular Ring Orbiting the Black Hole at the Galactic Center
• Very Large Array Observations of Galactic Center OH 1720 MHz Masers in Sagittarius A East and in the Circumnuclear Disk
• Excited-state OH Masers and Supernova Remnants

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