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Heterodyne spectroscopy of C II in molecular clouds

Betz, A. L. and Boreiko, R. T. and Zmuidzinas, J. (1990) Heterodyne spectroscopy of C II in molecular clouds. In: Submillimetre Astronomy. Astrophysics and Space Science Library. No.158. Springer Netherlands , Dordrecht, pp. 117-121. ISBN 9789401568524.

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High-resolution spectra of the 158 μm fine-structure line of ionized carbon have been obtained with a heterodyne spectrometer toward a number of galactic molecular clouds. Strongly reversed C II line profiles are seen in sources noted for similar behavior in low-J ¹²CO. The C⁺ producing the optically thick (τ≥1) absorption component is cool or subthermally excited, with excitation temperatures typically less than 25–50 K. Column densities for the absorption component are ≥10¹⁸ cm⁻², similar to values predicted by UV-photodissociation models for C II emitting gas. Thus the total C⁺ column density in the vicinity of these molecular clouds is significantly greater than previously estimated from integrated intensity measurements.

Item Type:Book Section
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Additional Information:© Springer Science+Business Media Dordrecht 1990. This work was supported in part by NASA under grant NAG2-254 for research in airborne astronomy.
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Subject Keywords:Optical Depth, Molecular Cloud, Column Density, Excitation Temperature, Line Reversal
Series Name:Astrophysics and Space Science Library
Issue or Number:158
Record Number:CaltechAUTHORS:20201205-161422499
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Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:106935
Deposited By: Rebecca Minjarez
Deposited On:10 Dec 2020 16:44
Last Modified:16 Nov 2021 18:58

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