Ammonia absorption toward W3 (OH) : 0".3 resolution maps in the (2,2)line.
Abstract
Maps with a spatial resolution of 0.26 arcsec x 0.26 arcsec are presented of the ammonia (2,2) inversion line in absorption against the continuum source W3(OH). It is shown that the ammonia cloud covers the western part of the continuum source, coinciding with the OH masers in front of the continuum. Evidence is also obtained for velocity and line width gradients within the NH3 cloud. The cloud is found to be clumpy with some structure on scales of 0.2 arcsec or less, while the sharp edges of the opacity maps at the boundary of the H II region indicate that the cloud probably extends as far as the OH masers. In addition, a high-sensitivity, high-resolution map of the H II region is obtained, which is found to agree very well with other maps of similar resolution at wavelengths of 1.0 and 2.0 cm. The high brightness temperatures show that part of the region is still optically thick at 1.3 cm. These findings indicate that the NH3 cloud may be a remnant accreting disk, whose inner part has been ionized by the UV radiation from a star of 50 solar masses.
- Publication:
-
Astronomy and Astrophysics
- Pub Date:
- October 1983
- Bibcode:
- 1983A&A...126...10G
- Keywords:
-
- Ammonia;
- Hydroxyl Emission;
- Interstellar Gas;
- Interstellar Masers;
- Molecular Absorption;
- Molecular Clouds;
- Accretion Disks;
- Astronomical Maps;
- Astronomical Models;
- H Ii Regions;
- Line Spectra;
- Radial Velocity;
- Astrophysics