Observations of interstellar H2O emission at 183 gigahertz

Abstract

view Abstract Citations (78) References (38) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Observations of interstellar H2O emission at 183 gigahertz Waters, J. W. ; Kakar, R. K. ; Kuiper, T. B. H. ; Roscoe, H. K. ; Swanson, P. N. ; Rodriguez Kuiper, E. N. ; Kerr, A. R. ; Thaddeus, P. ; Gustincic, J. J. Abstract Observations of the 183-GHz rotational transition of water vapor in interstellar molecular clouds are reported. The observations were made with a portable double-sideband superheterodyne radiometer used with the 91-cm Cassegrain telescope on board the Kuiper Airborne Observatory. An emission feature was detected in the direction of the Kleinmann-Low nebula in Orion with a peak antenna temperature of 15 K, a local standard of rest velocity of 8 km/sec, and a width of 15 km/sec. A plateau component of the emission profile is attributed to the 1-arcmin region characteristic of plateau emission from other observed molecules, with emission enhanced over that expected for thermal excitation, while the spike component observed is consistent with an optically thick source of the size of the molecular ridge in Orion at a temperature of 50 K and a column density greater than or equal to 3 x 10 to the 17th/sq cm, implying that H2O is one of the more abundant species in the Orion Molecular Cloud. Emission at 183 GHz was not detected in Sgr A, Sgr B2, W3, W43, W49, W51, DR 21, NGC 1333, NGC 7027, GL 2591 or the Rho Oph cloud; it may have been detected in M 17. Publication: The Astrophysical Journal Pub Date: January 1980 DOI: 10.1086/157609 Bibcode: 1980ApJ...235...57W Keywords: Infrared Astronomy; Interstellar Space; Microwave Emission; Nebulae; Radio Sources (Astronomy); Water Masers; Airborne Equipment; Brightness Temperature; Line Spectra; Molecules; Spectroscopic Telescopes; Astrophysics full text sources ADS |