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Discovery of a new population of galactic H II regions with ionized gas velocity gradients


Balser, DS and Wenger, TV and Anderson, LD and Armentrout, WP and Bania, TM and Dawson, JR and Dickey, JM, Discovery of a new population of galactic H II regions with ionized gas velocity gradients, Astrophysical Journal, 921, (2) pp. 1-17. ISSN 0004-637X (2021) [Refereed Article]

Copyright Statement

2021. The American Astronomical Society. All rights reserved.

DOI: doi:10.3847/1538-4357/ac1db3


We investigate the kinematic properties of Galactic H II regions using radio recombination line (RRL) emission detected by the Australia Telescope Compact Array at 4-10 GHz and the Jansky Very Large Array at 8-10 GHz. Our H II region sample consists of 425 independent observations of 374 nebulae that are relatively well isolated from other, potentially confusing sources and have a single RRL component with a high signal-to-noise ratio. We perform Gaussian fits to the RRL emission in position-position-velocity data cubes and discover velocity gradients in 178 (42%) of the nebulae with magnitudes between 5 and 200 m s(-1)arcsec(-1) II region simulations that include bipolar outflows or solid body rotational motions to explain the observed velocity gradients. The simulations favor solid body rotation since, unlike the bipolar outflow kinematic models, they are able to produce both the large, >40 m s(-1)arcsec(-1)

Item Details

Item Type:Refereed Article
Keywords:recombination line, angular-momentum, molecular cloud, massive stars, dark clouds, dense cores, HII-regions, kinematics, rotation, evolution
Research Division:Physical Sciences
Research Group:Astronomical sciences
Research Field:Galactic astronomy
Objective Division:Expanding Knowledge
Objective Group:Expanding knowledge
Objective Field:Expanding knowledge in the physical sciences
UTAS Author:Dawson, JR (Dr Joanne Dawson)
UTAS Author:Dickey, JM (Professor John Dickey)
ID Code:152793
Year Published:2021
Deposited By:Physics
Deposited On:2022-08-24
Last Modified:2022-09-19

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