Molecular clouds and cloud cores in the inner Galaxy

Journal Article · Wed Apr 01 04:00:00 EST 1987 · Astrophys. J., Suppl. Ser.; (United States)

DOI:https://doi.org/10.1086/191185· OSTI ID:6319582

Scoville, N Z; Yun, M SU; Sanders, D B; Clemens, D P; Waller, W H

A compilation of CO emission regions and their measured parameters is presented which represents a nearly complete accounting of the molecular clouds in the first quadrant of the Galaxy. Emission regions associated with radio H II regions have systematically brighter CO peaks that are a factor of two to three times larger and have twice the mean velocity dispersion as the general cloud population. Both the H II region clouds and the hot core regions have a Galactic distribution characteristic of a spiral arm population, whereas the colder clouds are much less confined in Galactic azimuthal angle. Virial masses are obtained for the large sample of clouds with assigned kinematic distances. The mean H2 density for a GMC of diameter 40 pc is 180/cm. For these clouds, a linear relationship is found between the H2 column density and the integrated CO emission. The variation in the Z-dispersion of clouds as a function of cloud mass suggests that more massive GMCs have smaller random velocities. 22 references.

• Research Organization: California Institute of Technology, Pasadena; Steward Observatory, Tucson, AZ; Massachusetts Univ., Amherst
• OSTI ID: 6319582
• Journal Information: Astrophys. J., Suppl. Ser.; (United States), Journal Name: Astrophys. J., Suppl. Ser.; (United States) Vol. 63; ISSN APJSA
• Country of Publication: United States
• Language: English

Related Subjects

640105* -- Astrophysics & Cosmology-- Galaxies
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
CARBON COMPOUNDS
CARBON MONOXIDE
CARBON OXIDES
CHALCOGENIDES
COSMIC GASES
COSMIC RADIO SOURCES
EMISSION SPECTRA
FLUIDS
GALAXIES
GASES
H2 REGIONS
LUMINOSITY
MASS
MILKY WAY
MOLECULES
NEBULAE
OPTICAL PROPERTIES
OXIDES
OXYGEN COMPOUNDS
PHYSICAL PROPERTIES
SPECTRA
STAR EVOLUTION