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Similar complex kinematics within two massive, filamentary infrared dark clouds?

Barnes, A. T., Henshaw, J. D., Caselli, P., Jiménez-Serra, I., Tan, J. C., Fontani, F., Pon, A. and Ragan, Sarah 2018. Similar complex kinematics within two massive, filamentary infrared dark clouds? Monthly Notices of the Royal Astronomical Society 475 (4) , pp. 5268-5289. 10.1093/mnras/sty173

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Abstract

Infrared dark clouds (IRDCs) are thought to be potential hosts of the elusive early phases of high-mass star formation. Here we conduct an in-depth kinematic analysis of one such IRDC, G034.43+00.24 (Cloud F), using high sensitivity and high spectral resolution IRAM-30m N2H+ (1 − 0) and C18O (1 − 0) observations. To disentangle the complex velocity structure within this cloud we use Gaussian decomposition and hierarchical clustering algorithms. We find that four distinct coherent velocity components are present within Cloud F. The properties of these components are compared to those found in a similar IRDC, G035.39-00.33 (Cloud H). We find that the components in both clouds have: high densities (inferred by their identification in N2H+), trans-to-supersonic non-thermal velocity dispersions with Mach numbers of ∼ 1.5 − 4, a separation in velocity of ∼ 3 km s−1, and a mean red-shift of ∼ 0.3 km s−1 between the N2H+ (dense gas) and C18O emission (envelope gas). The latter of these could suggest that these clouds share a common formation scenario. We investigate the kinematics of the larger-scale Cloud F structures, using lower-density-tracing 13CO (1 − 0) observations. A good correspondence is found between the components identified in the IRAM-30m observations and the most prominent component in the 13CO data. We find that the IRDC Cloud F is only a small part of a much larger structure, which appears to be an inter-arm filament of the Milky Way.

Item Type: Article
Date Type: Publication
Status: Published
Schools: Physics and Astronomy
Subjects: Q Science > QB Astronomy
Publisher: Oxford University Press
ISSN: 0035-8711
Date of First Compliant Deposit: 13 February 2018
Date of Acceptance: 17 January 2018
Last Modified: 05 Jun 2018 09:42
URI: http://orca.cf.ac.uk/id/eprint/109078

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