Observations of nonmetastable levels of interstellar ammonia

Abstract

view Abstract Citations (9) References (17) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Observations of nonmetastable levels of interstellar ammonia. Sweitzer, J. S. ; Palmer, P. ; Morris, M. ; Turner, B. E. ; Zuckerman, B. Abstract Results are reported for observations of microwave inversion radiation from short-lived excited rotational states (nonmetastable levels) of NH3 toward the Kleinmann-Low nebula (KLN) in Orion and toward Sgr B2. Emission from the (J, K) = (2, 1), (3, 2), (4, 3), and probably the (5, 4) inversion transitions were detected in the direction of the KLN; the (2, 1) line was detected toward Sgr B2, and negative results were obtained for six additional sources. Modeling of the observations indicates that the NH3 source in the KLN is small (about 10 to the 17th cm) and relatively hot (approximately 53.9 K), if LTE is a reasonable approximation, and that Sgr B2 appears to be extended (3 x 10 to the 19th cm) in the (2, 1) line and is relatively cool (no more than about 48 K), if the far-IR continuum excites the NH3. The results imply lower limits to the gas mass of 1 solar mass for the core of the KLN and 600,000 solar masses for the cool gas cloud in Sgr B2 Publication: The Astrophysical Journal Pub Date: January 1979 DOI: 10.1086/156746 Bibcode: 1979ApJ...227..415S Keywords: Ammonia; Interstellar Matter; Microwave Emission; Molecular Spectra; Nebulae; Radio Sources (Astronomy); Far Infrared Radiation; Molecular Excitation; Molecular Rotation; Radial Velocity; Astrophysics; Ammonia:Kleinmann-Low Nebula; Ammonia:Molecular Clouds; Kleinmann-Low Nebula:Microwave Radiation; Molecular Clouds:Radio Maps full text sources ADS |