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Published April 10, 2022 | Published + Accepted Version
Journal Article Open

Kinematics and Feedback in H ii Regions in the Dwarf Starburst Galaxy IC 10

Abstract

We present a survey of the central region of the nearest starburst galaxy, IC 10, using the W. M. Keck Observatory Keck Cosmic Web Imager (KCWI) at high spectral and spatial resolution. We map the central starburst of IC 10 to sample the kinematic and ionization properties of the individual star-forming regions. Using the low spectral resolution mode of KCWI, we map the oxygen abundance, and with the high spectral resolution mode, we identify 46 individual H II regions. These H II regions have an average radius of 4.0 pc, star formation rate ∼1.3 × 10⁻⁴ M⊙ yr⁻¹, and velocity dispersion ∼16 km s⁻¹. None of the H II regions appear to be virialized (α_(vir) ≫ 1), and on average, they show evidence of ongoing expansion. IC 10's H II regions are offset from the star-forming-region size–luminosity scaling relationships, as well as Larson's Law that relates size and velocity dispersion. We investigate the balance of inward and outward pressure, P_(in) and P_(out), finding P_(out) > P_(in) in 89% of H II regions, indicating feedback-driven expansion even in these low-mass H II regions. We find warm gas pressure (P_(gas)) provides the dominant contribution to the outward pressure (P_(out)). This counteracts the inward pressure, which is dominated by turbulence in the surrounding gas rather than self-gravity. Five H II regions show evidence of outflows that are most likely supported by either stellar winds (two regions) or champagne flows (three regions). These observations provide new insights into the state of the star-forming regions in IC 10 and negative feedback from low-mass clusters.

Additional Information

© 2022. The Author(s). Published by the American Astronomical Society. Original content from this work may be used under the terms of the Creative Commons Attribution 4.0 licence. Any further distribution of this work must maintain attribution to the author(s) and the title of the work, journal citation and DOI. Received 2021 October 13; revised 2022 January 20; accepted 2022 February 5; published 2022 April 14. We thank the anonymous referee for their comments that helped improve the quality of this paper. The data presented herein were obtained at the W. M. Keck Observatory, which is operated as a scientific partnership among the California Institute of Technology, the University of California, and the National Aeronautics and Space Administration. The Observatory was made possible by the generous financial support of the W. M. Keck Foundation. The authors wish to recognize and acknowledge the very significant cultural role and reverence that the summit of Maunakea has always had within the indigenous Hawaiian community. We are most fortunate to have the opportunity to conduct observations from this mountain. Facility: Keck: II (KCWI). - Software: astrodendro (Thomas et al. 2013), Astropy (Astropy Collaboration et al. 2013; Price-Whelan et al. 2018), IPython (Perez & Granger 2007) Matplotlib (Hunter 2007), NumPy (Harris et al. 2020), pandas (McKinney 2010; The Pandas Development Team 2016), photutils (Bradley et al. 2019), PyStan (Stan Development Team 2017), reproject (Robitaille et al. 2020), and SHAPE (Steffen et al. 2011).

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Published - Cosens_2022_ApJ_929_74.pdf

Accepted Version - 2202.04098.pdf

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Additional details

Created:
August 22, 2023
Modified:
October 24, 2023