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A Line Survey of Orion KL from 325 to 360 GHz

Schilke, P. and Groesbeck, T. D. and Blake, G. A. and Phillips, T. G. (1997) A Line Survey of Orion KL from 325 to 360 GHz. Astrophysical Journal Supplement Series, 108 (1). pp. 301-337. ISSN 0067-0049. http://resolver.caltech.edu/CaltechAUTHORS:20120914-095518465

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Abstract

We present a high-sensitivity spectral line survey of the high-mass star-forming region Orion KL in the 325-360 GHz frequency band. The survey was conducted at the Caltech Submillimeter Observatory on Mauna Kea, Hawaii. The sensitivity achieved is typically 0.1-0.5 K and is limited mostly by the sideband separation method utilized. We find 717 resolvable features consisting of 1004 lines, among which 60 are unidentified. The identified lines are due to 34 species and various isotopomers. Most of the unidentified lines are weak, and many of them most likely due to isotopomers or vibrationally or torsionally excited states of known species with unknown line frequencies, but a few reach the 2-5 K level. No new species have been identified, but we were able to strengthen evidence for the identification of ethanol in Orion and found the first nitrogen sulfide line in this source. The molecule dominating the integrated line emission is SO_2, which emits twice the intensity of CO, followed by SO, which is only slightly stronger than CO. In contrast, the largest number of lines is emitted from heavy organic rotors like HCOOCH_3, CH_3CH_2CN, and CH_3OCH_3, but their contribution to the total flux is unimportant. CH_3OH is also very prominent, both in the number of lines and in integrated flux. An interesting detail of this survey is the first detection of vibrationally excited HCN in the v_2 = 2 state, 2000 K above ground. Clearly this is a glimpse into the very inner part of the Orion hot core.


Item Type:Article
Related URLs:
URLURL TypeDescription
http://dx.doi.org/10.1086/312948DOIUNSPECIFIED
http://iopscience.iop.org/0067-0049/108/1/301/PublisherUNSPECIFIED
Additional Information:© 1997 American Astronomical Society. Received 1995 July 31; accepted 1996 June 27. The CSO is supported by NSF grant AST 93-13929. We would like to thank an anonymous referee and C. M. Walmsley for valuable comments. Special thanks to the maintainers of the JPL catalog, E. Herbst for making various spectoscopy data sets available in digital form, and E. Klisch and G. Winnewisser for providing 33SO frequencies prior to publication.
Funders:
Funding AgencyGrant Number
NSFAST 93-13929
Subject Keywords:ISM: abundances; ISM: individual (Orion Kleinmann-Low); line: identification; radio lines: ISM
Record Number:CaltechAUTHORS:20120914-095518465
Persistent URL:http://resolver.caltech.edu/CaltechAUTHORS:20120914-095518465
Official Citation:A Line Survey of Orion KL from 325 to 360 GHz P. Schilke et al. 1997 ApJS 108 301
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:34086
Collection:CaltechAUTHORS
Deposited By: Ruth Sustaita
Deposited On:14 Sep 2012 17:50
Last Modified:26 Dec 2012 16:10

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