Detection of interstellar NH/sub 3/ in the far-warm and dense gas in Orion-KL

Technical Report · Fri Jan 01 00:00:00 EST 1982

OSTI ID:5831839

Townes, C H; Gentzel, R

The detection of the (J,K) a(4,3) yields s(3,3) rotation inversion transition of ammonia at 124.6 microns toward the center of the Orion-KL region is reported. The line is in emission and has a FWHM or to 30 km s 0.15. The far IR ammonia line emission problably comes mainly from the 'hot core', a compact region of warm, very dense gas previously identified by the radio inversion lines of NH3. The a(4,3) yields s(3,3) line is very optically thick, and since it is seen in emission, radiative excitation of the (4,3) NH3 level by far IR emission from dust within the source can be ruled out. Radiative excitation via the 10 microns of vibrational transitions of NH3 also seems unlikely. Hence, the (4,3) level is probably collisionally excited and the gas in the hot core region is warmer than the dust. Since the far IR line emission is highly trapped, densities of approximately 10 to the 7th power cu cm are high enough to explain the observations. Shock heating by the mass outflow from IRc2 may account for the high gas temperatures in the hot core region.

• Research Organization: California Univ., Berkeley (USA)
• OSTI ID: 5831839
• Report Number(s): N-8318622
• Country of Publication: United States
• Language: English

Related Subjects

640105* -- Astrophysics & Cosmology-- Galaxies
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
AMMONIA
ELECTROMAGNETIC RADIATION
EMISSION SPECTRA
ENERGY LEVELS
ENERGY-LEVEL TRANSITIONS
EXCITATION
EXCITED STATES
FAR INFRARED RADIATION
HYDRIDES
HYDROGEN COMPOUNDS
INFRARED RADIATION
INTERSTELLAR SPACE
NEBULAE
NITROGEN COMPOUNDS
NITROGEN HYDRIDES
RADIATIONS
ROTATIONAL STATES
SPACE
SPECTRA