Ionised gas kinematics in bipolar H II regions

Dalgleish, Hannah S and Longmore, Steven N and Peters, Thomas and Henshaw, Jonathan D and Veitch-Michaelis, Joshua L and Urquhart, J.S. (2018) Ionised gas kinematics in bipolar H II regions. Monthly Notices of the Royal Astronomical Society, . ISSN 0035-8711. (doi:https://doi.org/10.1093/mnras/sty1109) (Full text available)

Abstract

Stellar feedback plays a fundamental role in shaping the evolution of galaxies. Here we explore the use of ionised gas kinematics in young, bipolar H II regions as a probe of early feedback in these star-forming environments. We have undertaken a multi-wavelength study of a young, bipolar H II region in the Galactic disc, G316.81–0.06, which lies at the centre of a massive (∼103 M⊙) infrared-dark cloud filament. It is still accreting molecular gas as well as driving a ∼0.2 pc ionised gas outflow perpendicular to the filament. Intriguingly, we observe a large velocity gradient (47.81 ± 3.21 km s−1 pc−1) across the ionised gas in a direction perpendicular to the outflow. This kinematic signature of the ionised gas shows a reasonable correspondence with the simulations of young H II regions. Based on a qualitative comparison between our observations and these simulations, we put forward a possible explanation for the velocity gradients observed in G316.81–0.06. If the velocity gradient perpendicular to the outflow is caused by rotation of the ionised gas, then we infer that this rotation is a direct result of the initial net angular momentum in the natal molecular cloud. If this explanation is correct, this kinematic signature should be common in other young (bipolar) H II regions. We suggest that further quantitative analysis of the ionised gas kinematics of young H II regions, combined with additional simulations, should improve our understanding of feedback at these early stages.

Item Type:	Article
Uncontrolled keywords:	ISM: H II regions, kinematics and dynamics - stars: massive, protostars
Divisions:	Faculties > Sciences > School of Physical Sciences Faculties > Sciences > School of Physical Sciences > Centre for Astrophysics and Planetary Sciences
Depositing User:	James Urquhart
Date Deposited:	10 May 2018 15:50 UTC
Last Modified:	24 May 2018 10:56 UTC
Resource URI:	https://kar.kent.ac.uk/id/eprint/66988 (The current URI for this page, for reference purposes)
Urquhart, J.S.:	https://orcid.org/0000-0002-1605-8050