Green Bank Telescope observations of the NH3 (3, 3) and (6, 6) transitions toward sagittarius a molecular clouds

Abstract

Ammonia (3, 3) and (6, 6) transitions have been observed using the Green Bank Telescope toward the Sgr A region. The gas is mainly concentrated in 50 km s-1 and 20 km s-1 clouds located in a plane inclined to the galactic plane. These "main" clouds appear to be virialized and influenced by the expansion of the supernova remnant Sgr A East. The observed emission shows very complicated features in the morphology and velocity structure. Gaussian multi-component fittings of the observed spectra revealed that various "streaming" gas components exist all over the observed region. These components include those previously known as "streamers" and "ridges," but most of these components appear not to be directly connected to the major gas condensations (the 50 km s-1 and 20 km s-1 clouds). They are apparently located out of the galactic plane, and they may have a different origin than the major gas condensations. Some of the streaming components are expected to be sources that feed the circumnuclear disk of our Galactic center directly and episodically. They may also evolve differently than major gas condensations under the influence of the activities of the Galactic center. © 2013. The American Astronomical Society. All rights reserved.