Molecular line observations of infrared dark clouds: seeking the precursors to intermediate and massive star formation

Ragan, Sarah ORCID: https://orcid.org/0000-0003-4164-5588, Bergin, Edwin, Plume, Rene, Gibson, D, Wilner, David, O'Brien, S and Hails, E 2006. Molecular line observations of infrared dark clouds: seeking the precursors to intermediate and massive star formation. Astrophysical Journal Supplement 166 (2) , pp. 567-584. 10.1086/506594

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Abstract

We have identified 41 infrared dark clouds from the 8 μm maps of the Midcourse Space Experiment (MSX), selected to be found within 1 deg2 areas centered on known ultracompact H II regions. We have mapped these infrared dark clouds in N2H+1-->0, CS 2-->1, and C18O 1-->0 emission using the Five College Radio Astronomy Observatory. The maps of the different species often show striking differences in morphologies, indicating differences in evolutionary state and/or the presence of undetected, deeply embedded protostars. We derive an average mass for these clouds using N2H+ column densities of ~2500 Msolar, a value comparable to that found in previous studies of high-mass star-forming cores using other mass tracers. The line widths of these clouds are typically ~2.0-2.9 km/s. Based on the fact that they are dark at 8 μm, compact, and massive, and have large velocity dispersions, we suggest that these clouds may be the precursor sites of intermediate- and high-mass star formation.

Item Type:	Article
Date Type:	Publication
Status:	Published
Schools:	Physics and Astronomy
Subjects:	Q Science > QB Astronomy
Publisher:	American Astronomical Society
ISSN:	0067-0049
Date of First Compliant Deposit:	27 November 2017
Date of Acceptance:	6 June 2006
Last Modified:	05 May 2023 22:39
URI:	https://orca.cardiff.ac.uk/id/eprint/106492

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