A thermal plume in NGC 2024

Subrahmanyan, Ravi ; Goss, W. M. ; Megeath, S. T. ; Barnes, Peter J. (1997) A thermal plume in NGC 2024 Monthly Notices of the Royal Astronomical Society, 290 (3). pp. 431-438. ISSN 0035-8711

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Official URL: https://academic.oup.com/mnras/article/290/3/431/9...

Related URL: http://dx.doi.org/10.1093/mnras/290.3.431


We present 1-arcmin resolution radio images of the Galactic H II region NGC 2024 made at 0.33 and 10.55 GHz. These are the highest dynamic range images of the nebula to date. The peak brightness in the 0.33-GHz radio continuum image indicates that the electron temperature is 6800–7600 K. The images clarify the structure of a thermal plume that is directed north from the H II region and opposite to a unipolar molecular outflow found in the molecular cloud near the H II region. We report the detection of H91α recombination lines from the plume: these data confirm that the plume is blueshifted relative to the molecular cloud. Finally, we discuss the relative merits of three possible explanations for the plume: that the plume results from the blueshifted counterjet to the CO outflow; that the plume is the continuation of the champagne flow observed in the denser parts of the H II region; and that the plume is produced by the photoevaporation of molecular clumps apparent in a 13CO map of the region.

Item Type:Article
Source:Copyright of this article belongs to Oxford University Press.
Keywords:H n Regions; ISM: Individual: NGC 2024; ISM: Jets and Outflows; Radio Continuum: ISM; Radio Lines: ISM
ID Code:114382
Deposited On:21 May 2018 08:04
Last Modified:21 May 2018 08:04

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