Properties of the galactic molecular cloud ensemble from observations of /sup 13/CO

Journal Article · Thu Oct 15 00:00:00 EDT 1981 · Astrophys. J.; (United States)

DOI:https://doi.org/10.1086/159313· OSTI ID:5526554

Liszt, H S; Delin, X; Burton, W B

We have observed galactic /sup 13/CO over the region b = 0/sup 0/, l = 28/sup 0/--40/sup 0/, at 3' spacings of the 36 foot (11 m) telescope antenna pattern. The major results of interpretation of these observations are as follows: (1) The size distribution of molecular clouds, inferred from correction measured sizes of features for the bias introduced by sampling only at b = 0/sup 0/, is characterized by the moments < or approx. =25 pc, /sup 1/2/< or approx. =27 pc, /sup 1/3/< or approx. =29 pc. (2) The smallest mean density of hydrogen molecules derived for the region Rroughly-equal5 kpc consistent with available constraints is roughly-equal2.5 cm/sup -3/. Higher values may easily be derived; lower ones are difficult to justify. (3) The radial abundance variations of the /sup 13/CO emissivity follows the general behavior established earlier from /sup 12/CO, but with prominent enhancements (in the longitude region observed) at Rroughly-equal9--10 kpc and Rroughly-equal7--8 kpc. (4) Comparison of the longitudinal variation of terminal velocities measured in /sup 13/CO and in H I indicates that the galactic kinematics of the dense centered molecular clouds are essentially identical to those found for H I. (5) Comparison of /sup 13/CO and H I integrated intensities indicates that one may find substantial regions over each of which the atomic and molecular intensities may be strongly positively or anticorrelated, or statistically independent. Reasons for this behavior are summarized here and considered in more detail by Liszt, Burton, and Bania.

• Research Organization: National Radio Astronomy Observatory
• OSTI ID: 5526554
• Journal Information: Astrophys. J.; (United States), Vol. 249:2
• Country of Publication: United States
• Language: English

Related Subjects

71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
CARBON MONOXIDE
MILKY WAY
ABUNDANCE
CHEMICAL COMPOSITION
EMISSION
ENERGY SPECTRA
HYDROGEN
INTERSTELLAR SPACE
MOLECULES
RADIOWAVE RADIATION
SPATIAL DISTRIBUTION
CARBON COMPOUNDS
CARBON OXIDES
CHALCOGENIDES
DISTRIBUTION
ELECTROMAGNETIC RADIATION
ELEMENTS
GALAXIES
NONMETALS
OXIDES
OXYGEN COMPOUNDS
RADIATIONS
SPACE
SPECTRA
640105* - Astrophysics &amp; Cosmology- Galaxies