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CO J = 2-1 mapping of NGC 1976

White, Glenn J. and Phillips, J. P. (1988). CO J = 2-1 mapping of NGC 1976. Astronomy and Astrophysics, 197(1-2) pp. 253–260.

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The authors present 77 CO J = 2-1 spectra centred upon four areas about the periphery of the Orion nebula NGC 1976. These reveal evidence of extensive line splitting, with primary components at VLSR ~ 12 km s-1 and VLSR ~ 7 km s-1. The spatial structure of the regions responsible for these components appears to differ appreciably, and various arguments are outlined to suggest that two distinct segments of a single enveloping cloud are responsible; one to the rear of the H II region (VLSR ~ 7 km s-1), associated with various star formation zones, the other in front of NGC 1976, and responsible for localised foreground extinction. This contrasts with previous models, which have proposed compressive shock regions ahead of local ionisation fronts; an hypothesis which is shown not to be necessary, and may be inconsistent with the observed width and conformity of the line splitting zone.

Item Type: Journal Article
Copyright Holders: 1988 European Southern Observatory
ISSN: 1432-0746
Keywords: astronomical maps; astronomical spectroscopy; carbon monoxide; Orion nebula; forbidden transitions; HII regions; interstellar extinction; molecular clouds; star formation
Academic Unit/Department: Science > Physical Sciences
Interdisciplinary Research Centre: Centre for Earth, Planetary, Space and Astronomical Research (CEPSAR)
Item ID: 33348
Depositing User: Glenn White
Date Deposited: 18 Apr 2012 15:01
Last Modified: 05 Mar 2014 12:47
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