NH/sub 3/ in Orion-KL: A new interpretation

Journal Article · Sun Aug 15 04:00:00 EDT 1982 · Astrophys. J., Lett. Ed.; (United States)

DOI:https://doi.org/10.1086/183856· OSTI ID:6865125

Genzel, R; Downes, D; Ho, P T.P.; Beiging, J

We interpret the observations of ammonia in Orion-KL in a way which greatly simplifies the understanding of single-dish and VLA data. In this new picture, there are only two velocity components: the ''spike'' component from the quiscent molecular cloud and the ''hot core'' component from both streaming and ''stationary'' gas in the 18 km s/sup -1/ outflow from the compact infrared source IRc2. What has been interpreted previously as the NH/sub 3/ ''plateau'' from high-velocity gas is mainly the blended hyperfine satellite emission from the ''hot core'' component. The ammonia lines are highly optically thick (tau>10), and NH/sub 3/ column densities reach 5 x 10/sup 18/ cm/sup -2/. Kinetic temperatures in the outflow region are about 200 K, and NH/sub 3/ is probably collisionally excited at hydrogen densities of 10/sup 8/--10/sup 9/ cm/sup -3/. Ammonia may be highly overabundant in this dense and warm gas and may tie up a considerable fraction of the available nitrogen. The maps can be interpreted as showing a clumpy, expanding, and turbulent shell advancing into the densest part of the Orion-KL region.

• Research Organization: Department of Physics, University of California, Berkeley
• OSTI ID: 6865125
• Journal Information: Astrophys. J., Lett. Ed.; (United States), Journal Name: Astrophys. J., Lett. Ed.; (United States) Vol. 259:2; ISSN AJLEA
• Country of Publication: United States
• Language: English

Related Subjects

640105* -- Astrophysics & Cosmology-- Galaxies
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
AMMONIA
COSMIC RADIO SOURCES
ELECTROMAGNETIC RADIATION
FUNCTIONS
HYDRIDES
HYDROGEN COMPOUNDS
INFRARED RADIATION
INTERSTELLAR GRAINS
MAPS
NEBULAE
NITROGEN COMPOUNDS
NITROGEN HYDRIDES
OPACITY
OPTICAL PROPERTIES
PARTICLES
PHYSICAL PROPERTIES
RADIATIONS
RADIOWAVE RADIATION
SPECTRA
SPECTRAL DENSITY
SPECTRAL FUNCTIONS