Anomalous ammonia absorption in DR 21

Journal Article · Wed Jun 01 04:00:00 EDT 1977 · Astrophys. J., Lett.; (United States)

DOI:https://doi.org/10.1086/182445· OSTI ID:7215222

Matsakis, D N; Brandshaft, D; Chui, M F; Cheung, A C; Yngvesson, K S; Cardiasmenos, A G; Shanley, J F; Ho, P T.P.

Ammonia has been detected for the first time in absorption, against the strong radio continuum source DR 21, and the inferred optical depth is further evidence for clumping. Some of the hyperfine components are observed in emission and some in absorption, indicating deviations of the level populations on the order of a few percent from LTE. An infrared trapping model requires that the cloud be fragmented into clumps of size less than 0.2 pc with velocity widths of about 0.3 km s/sup -1/.

• Research Organization: University of California, Berkeley, California 94720
• OSTI ID: 7215222
• Journal Information: Astrophys. J., Lett.; (United States), Journal Name: Astrophys. J., Lett.; (United States) Vol. 214:2; ISSN AJLEA
• Country of Publication: United States
• Language: English

Related Subjects

640103* -- Astrophysics & Cosmology-- Quasi-Stellar
Radio
& X-Ray Sources-- (-1987)
640105 -- Astrophysics & Cosmology-- Galaxies
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
AMMONIA
CHEMICAL COMPOSITION
CHEMISTRY
COSMIC RADIO SOURCES
COSMOCHEMISTRY
COSMOLOGICAL MODELS
ELECTROMAGNETIC RADIATION
ENERGY SPECTRA
ENERGY-LEVEL TRANSITIONS
H2 REGIONS
HYDRIDES
HYDROGEN COMPOUNDS
INTERSTELLAR SPACE
MATHEMATICAL MODELS
MOLECULES
NITROGEN COMPOUNDS
NITROGEN HYDRIDES
RADIATIONS
RADIOWAVE RADIATION
SPACE
SPECTRA