The detailed structure of CO in molecular cloud complexes. II. The W75-DR21 region.
Abstract
Analysis of 12CO and 13CO spectral4ine maps of the DR 21-W75 complex has revealed the presence of two large molecular clouds, one at a radial velocity of -3 km s - and the other at an average velocity near +9 km s '. Recognition of features common to both velocities suggests that the two clouds are interacting. The line profiles of the -3 km -1 component exhibit a broad wing structure at all positions across the cloud, which has a radius greater than 10 pc. This is the first reported case of such wide wings on the CO line over an extended area of the sky. Comparison of the profiles with model calculations suggests that this cloud may be in overall gravitational collapse. The compact H ii region DR 21 and several other condensations are embedded in this cloud, and the CO exhibits peaks at these sources. The +9 km s - cloud is less dense and shows a gradient in radial velocity across its face that is possibly caused by a differential retardation as it passes around the edge of the other component. The faint, compact H ii region W75 N lies in this +9km s ' cloud. Subject headings: interstellar: matter - interstellar: molecules - nebulae: individual
- Publication:
-
The Astrophysical Journal
- Pub Date:
- August 1978
- DOI:
- 10.1086/156317
- Bibcode:
- 1978ApJ...223..840D
- Keywords:
-
- Carbon Monoxide;
- Interstellar Gas;
- Molecular Spectra;
- Nebulae;
- Astronomical Maps;
- Astronomical Models;
- Hydrogen Clouds;
- Line Shape;
- Line Spectra;
- Astrophysics;
- Carbon Monoxide:Molecular Clouds;
- H II Regions:Molecular Clouds