Universität zu Köln

Lo, N., Cunningham, M. R., Jones, P. A., Bronfman, L., Cortes, P. C., Simon, R., Lowe, V., Fissel, L. and Novak, G. (2014). TRACING H-2 COLUMN DENSITY WITH ATOMIC CARBON (C I) AND CO ISOTOPOLOGS. Astrophys. J. Lett., 797 (2). BRISTOL: IOP PUBLISHING LTD. ISSN 2041-8213

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Abstract

We present the first results of neutral carbon ([C I](3) P-1-P-3(0) at 492 GHz) and carbon monoxide ((CO)-C-13, J = 1-0) mapping in the Vela Molecular Ridge cloud C (VMR-C) and the G333 giant molecular cloud complexes with the NANTEN2 and Mopra telescopes. For the four regions mapped in this work, we find that [C I] has very similar spectral emission profiles to (CO)-C-13, with comparable line widths. We find that [C I] has an opacity of 0.1-1.3 across the mapped region while the [C I]/(CO)-C-13 peak brightness temperature ratio is between 0.2 and 0.8. The [C I] column density is an order of magnitude lower than that of (CO)-C-13. The H-2 column density derived from [C I] is comparable to values obtained from (CO)-C-12. Our maps show that C I is preferentially detected in gas with low temperatures (below 20 K), which possibly explains the comparable H-2 column density calculated from both tracers (both C I and (CO)-C-12 underestimate column density), as a significant amount of the C I in the warmer gas is likely in the higher energy state transition ([C I](3) P-2-P-3(1) at 810 GHz), and thus it is likely that observations of both the above [C I] transitions are needed in order to recover the total H-2 column density.

Item Type:	Journal Article
Creators:	Creators Email ORCID ORCID Put Code Lo, N. UNSPECIFIED UNSPECIFIED UNSPECIFIED Cunningham, M. R. UNSPECIFIED UNSPECIFIED UNSPECIFIED Jones, P. A. UNSPECIFIED UNSPECIFIED UNSPECIFIED Bronfman, L. UNSPECIFIED UNSPECIFIED UNSPECIFIED Cortes, P. C. UNSPECIFIED UNSPECIFIED UNSPECIFIED Simon, R. UNSPECIFIED UNSPECIFIED UNSPECIFIED Lowe, V. UNSPECIFIED UNSPECIFIED UNSPECIFIED Fissel, L. UNSPECIFIED UNSPECIFIED UNSPECIFIED Novak, G. UNSPECIFIED UNSPECIFIED UNSPECIFIED
URN:	urn:nbn:de:hbz:38-420042
DOI:	10.1088/2041-8205/797/2/L17
Journal or Publication Title:	Astrophys. J. Lett.
Volume:	797
Number:	2
Date:	2014
Publisher:	IOP PUBLISHING LTD
Place of Publication:	BRISTOL
ISSN:	2041-8213
Language:	English
Faculty:	Unspecified
Divisions:	Unspecified
Subjects:	no entry
Uncontrolled Keywords:	Keywords Language GIANT MOLECULAR CLOUD; REGION G333.6-0.2; HII-REGIONS; EMISSION; MASERS; VELA; RADIO; GHZ Multiple languages Astronomy & Astrophysics Multiple languages
URI:	http://kups.ub.uni-koeln.de/id/eprint/42004