Astronomical observations of the 807-GHz CO J = 7-6 rotational line with a new heterodyne spectrometer

Thesis/Dissertation · Wed Jan 01 04:00:00 EST 1986

OSTI ID:6640240

Harris, A I

The submillimeter of carbon monoxide (CO) are a valuable new tool for the study of warm (50 to 500K) molecular material in the interstellar medium. This presence of a large amount of gas with temperatures of a few hundred degrees ear luminous sources has only recently been revealed by far-infrared and submillimeter molecular line observations. The author studied the CO J = 7 ..-->.. 6 and (CI) /sup 3/P/sub 2/ ..-->.. /sup 3/P/sub 1/ lines toward several regions with a new heterodyne spectrometer. He reports here the first detection and mapping of CO J = 7 ..-->.. 6 line emission in the central 10 pc of the Galaxy. The CO 7 ..-->.. 6 line at 806.65 GHz (372 ..mu..m) comes from a dense, clumpy ring or disk (n/sub H2/ approx. = 3 x 10/sup 4/ cm/sup -3/, mass approx. = 10/sup 4/ solar masses of temperature approx.300 K. The luminosity of all CO rotational lines emitted from this approx.4' diameter region is about 2 x 10/sup 4/ solar luminosities. CO line emission is a major contribution to the cooling of the interstellar gas near Sqr A. UV radiation from the Galactic center could heat the molecular gas if CO self-shielding is effective. Alternatively, cloud-cloud collisions or mass outflow from the center may cause shocks which heat the war molecular gas. The CO data confirm that neutral ring rotates about the center with a rotation axis close to that of general galactic rotation. The submillimeter CO data also suggest that the velocity centroids along the galactic plane drop by a factor of 1.4 to 2 between 2 and 6 pc from the center.

• Research Organization: California Univ., Berkeley (USA)
• OSTI ID: 6640240
• 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
FREQUENCY RANGE
GALAXIES
GHZ RANGE
GHZ RANGE 100-1000
INTERSTELLAR SPACE
LUMINOSITY
MICROWAVE SPECTRA
MILKY WAY
OPTICAL PROPERTIES
OXIDES
OXYGEN COMPOUNDS
PHYSICAL PROPERTIES
SPACE
SPECTRA