Temperatures of galactic molecular clouds showing CO self-absorption.
Abstract
The CO J = 2-1 line has been observed and, in most cases, mapped in 10 star-forming molecular clouds (W3, NGC 1333, NGC 2071, Mon R2, CRL 961, Rho Oph, W49N, W51A, DR 21, and Cep A). The CO J = 3-2 line has been observed in W3 and DR 21. The CO lines from all these sources are strongly self-absorbed. By comparing the present results with published CO(1-0) line profiles, it is found that large corrections to the temperatures of the cloud cores, as measured by the CO(1-0) lines, are required. The corrections for self-absorption bring the CO brightness temperatures into closer agreement with the grain temperatures inferred from far-IR photometry.
- Publication:
-
The Astrophysical Journal
- Pub Date:
- April 1981
- DOI:
- 10.1086/158826
- Bibcode:
- 1981ApJ...245..512P
- Keywords:
-
- Carbon Monoxide;
- Gas Temperature;
- Interstellar Gas;
- Molecular Clouds;
- Nebulae;
- Self Absorption;
- Astronomical Models;
- Brightness Temperature;
- Emission Spectra;
- Line Spectra;
- Spectral Line Width;
- Spectrum Analysis;
- Stellar Evolution;
- Thermodynamic Equilibrium;
- Astronomy