title: Submillimeter heterodyne detection of interstellar carbon monoxide at 434 micrometers.
abstract: A submillimeter heterodyne radiometer, developed for astronomical applications, uses an optically pumped laser local oscillator and a quasi-optical Schottky diode mixer. The resultant telescope-mounted system, which has a noise temperature less than 4000 K (double sideband) and high frequency and spatial resolution, has been used to detect the J = 6 --> 5 rotational transition of carbon monoxide at 434 micrometers in the Orion molecular cloud. The measurements, when compared with previous millimeter-wave data, indicate that the broad carbon monoxide emission feature is produced by an optically thin gas whose temperature exceeds 180 K.
authors.forename: H R
authors.initials: HR
authors.lastname: Fetterman
authors.forename: G A
authors.initials: GA
authors.lastname: Koepf
authors.forename: P F
authors.initials: PF
authors.lastname: Goldsmith
authors.forename: B J
authors.initials: BJ
authors.lastname: Clifton
authors.forename: D
authors.initials: D
authors.lastname: Buhl
authors.forename: N R
authors.initials: NR
authors.lastname: Erickson
authors.forename: D D
authors.initials: DD
authors.lastname: Peck
authors.forename: N
authors.initials: N
authors.lastname: McAvoy
authors.forename: P E
authors.initials: PE
authors.lastname: Tannenwald