Submillimeter Heterodyne Detection of Interstellar Carbon Monoxide at 434 Micrometers

See allHide authors and affiliations

Science  06 Feb 1981:
Vol. 211, Issue 4482, pp. 580-582
DOI: 10.1126/science.211.4482.580


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 = 65 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.