The density structure of molecular cloud cores
Abstract
Multitransition studies using CS, C-34S, and H2CO have been conducted for the dense cores of the molecular clouds M17, S140, and NGC 2024. The gas densities derived from these three molecules are in reasonable agreement. The typical peak density in these cores is about one-million/cu cm, much larger than the average density in molecular clouds, but the gas density is not strongly correlated with the line intensities within the core itself. Rather, a map of line intensity appears to be a map of column density and filling factor. Density is revealed only by the ratios of intensities of different lines. Although the data do not have the spatial resolution to directly 'see' clumps, statistical equilibrium modeling of the data does provide evidence for density variations within the beam. These data will be essential to efforts to convert spatial maps obtained with large millimeter dishes or interferometers into maps of density structure.
- Publication:
-
Millimeter and Submillimeter Wave Radio Astronomy
- Pub Date:
- 1985
- Bibcode:
- 1985mswr.symp..247E
- Keywords:
-
- Gas Density;
- Molecular Clouds;
- Molecular Excitation;
- Carbon Compounds;
- Carbon Monoxide;
- Formaldehyde;
- Least Squares Method;
- Statistical Analysis;
- Sulfur Compounds;
- Astrophysics