Barnes, AT, Glover, SCO, Kreckel, K, Ostriker, EC, Bigiel, F, Belfiore, F, Bešlić, I, Blanc, GA, Chevance, M, Dale, DA, Egorov, O, Eibensteiner, C, Emsellem, E, Grasha, K, Groves, BA, Klessen, RS, Kruijssen, JMD, Leroy, AK, Longmore, SN, Lopez, L et al, McElroy, R, Meidt, SE, Murphy, EJ, Rosolowsky, E, Saito, T, Santoro, F, Schinnerer, E, Schruba, A, Sun, J, Watkins, EJ and Williams, TG (2021) Comparing the pre-SNe feedback and environmental pressures for 6000 HII regions across 19 nearby spiral galaxies. Monthly Notices of the Royal Astronomical Society, 508 (4). pp. 5362-5389. ISSN 0035-8711

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Abstract

The feedback from young stars (i.e. pre-supernova) is thought to play a crucial role in molecular cloud destruction. In this paper, we assess the feedback mechanisms acting within a sample of 5810 HII regions identified from the PHANGS-MUSE survey of 19 nearby ($<$ 20 Mpc) star-forming, main sequence spiral galaxies (log($M_\star$/M$_\odot$)= 9.4 $-$ 11). These optical spectroscopic maps are essential to constrain the physical properties of the HII regions, which we use to investigate their internal pressure terms. We estimate the photoionised gas ($P_\mathrm{therm}$), direct radiation ($P_\mathrm{rad}$), and mechanical wind pressure ($P_\mathrm{wind}$), which we compare to the confining pressure of their host environment ($P_\mathrm{de}$). The HII regions remain unresolved within our ${\sim}50{-}100$ pc resolution observations, so we place upper ($P_\mathrm{max}$) and lower ($P_\mathrm{min}$) limits on each of the pressures by using a minimum (i.e. clumpy structure) and maximum (i.e. smooth structure) size, respectively. We find that the $P_\mathrm{max}$ measurements are broadly similar, and for $P_\mathrm{min}$ the $P_\mathrm{therm}$ is mildly dominant. We find that the majority of HII regions are over-pressured, $P_\mathrm{tot}/P_\mathrm{de} = (P_\mathrm{therm}+P_\mathrm{wind}+P_\mathrm{rad})/P_\mathrm{de} > 1$, and expanding, yet there is a small sample of compact HII regions with $P_\mathrm{tot,max}/P_\mathrm{de} < 1$ ($\sim$1% of the sample). These mostly reside in galaxy centres ($R_\mathrm{gal}<1$kpc), or, specifically, environments of high gas surface density; log($\Sigma_\mathrm{gas}/\mathrm{M_\odot} \mathrm{pc}^{-2}$)$\sim$2.5 (measured on kpc-scales). Lastly, we compare to a sample of literature measurements for $P_\mathrm{therm}$ and $P_\mathrm{rad}$ to investigate how dominant pressure term transitions over around 5dex in spatial dynamic range and 10 dex in pressure.

Item Type:	Article
Additional Information:	This article has been accepted for publication in Monthly Notices of the Royal Astronomical Society ©: 2021 The Authors Published by Oxford University Press on behalf of the Royal Astronomical Society. All rights reserved.
Uncontrolled Keywords:	astro-ph.GA; astro-ph.GA; astro-ph.SR
Subjects:	Q Science > QB Astronomy Q Science > QC Physics
Divisions:	Astrophysics Research Institute
Publisher:	Oxford University Press
Related URLs:	http://arxiv.org/abs/2110.05492v1
Date Deposited:	25 Oct 2021 09:53
Last Modified:	24 Nov 2021 12:00
DOI or ID number:	10.1093/mnras/stab2958
URI:	https://researchonline.ljmu.ac.uk/id/eprint/15694

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