Warm and Diffuse Gas near the Galactic Center probed by Metastable H3+
Abstract
Using observations of a line from the metastable (3,3) rotational level of H3+ combined with measurements of other lines of H3+ and CO, we have discovered a large quantity of high temperature (T ∼250K) and low density (n ∼100 cm-3) gas within the central few hundred parsecs of the Galaxy. Some of this gas has velocities near -100 km s-1 (LSR) and apparently is associated with the Expanding Molecular Ring at a distance of 180 pc from the nucleus; most of the remainder is at velocities near -50, 0, and + 50 km s-1. Previous interpretations of the interstellar gas in the central few hundred parsecs have been that it is mostly in the form of dense clouds which have a filling factor of ∼0.1. The observations reported here suggest that the filling factor of dense gas is much smaller than this. The metastable H3+ level is not populated in a number of star-forming clouds far from the Galactic Center.
- Publication:
-
American Astronomical Society Meeting Abstracts #206
- Pub Date:
- May 2005
- Bibcode:
- 2005AAS...206.3701G