CH observations of diffuse molecular clouds

Journal Article · Sat Apr 01 04:00:00 EST 1989 · Astrophys. J.; (United States)

DOI:https://doi.org/10.1086/167292· OSTI ID:5841776

Magnani, L; Lada, E A; Sandell, G; Blitz, L

A survey of CH 3.3 GHz emission from a sample of high-latitude molecular clouds, diffuse clouds, and heavily reddened globular clusters is presented. The F = 1-1 main-line transition was detected in every molecular cloud in the sample and in two out of four globular cluster lines of sight. The high rate of detections in the low-extinction high-latitude clouds indicates that the CH hyperfine ground-state transitions are at least as efficient low-density molecular gas tracers as the CO rotational transitions. The CH column densities and abundances with respect to H(total) determined for the molecular clouds are consistent with predictions of equilibrium chemistry models for clouds of low extinction and density. Upper limits to the CH abundance for four IRAS cirrus clouds are also consistent with chemistry models for the predominantly atomic hydrogen, warm low-density diffuse clouds which constitute a significant fraction of the interstellar medium. 55 refs.

• Research Organization: Arecibo Observatory (Puerto Rico); Texas Univ., Austin (USA); Joint Astronomy Center, Hilo, HI (USA); Maryland Univ., College Park (USA); Institute for Advanced Study, Princeton, NJ (USA)
• OSTI ID: 5841776
• Journal Information: Astrophys. J.; (United States), Journal Name: Astrophys. J.; (United States) Vol. 339; ISSN ASJOA
• Country of Publication: United States
• Language: English

Related Subjects

640105* -- Astrophysics & Cosmology-- Galaxies
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
ABUNDANCE
CHEMICAL COMPOSITION
CHEMISTRY
COSMOCHEMISTRY
DENSITY
ENERGY LEVELS
ENERGY-LEVEL TRANSITIONS
GROUND STATES
HYDROCARBONS
INTERSTELLAR SPACE
LIMITING VALUES
MOLECULES
ORGANIC COMPOUNDS
PHYSICAL PROPERTIES
SATELLITES
SPACE
STAR CLUSTERS