Comparing the pre-SNe feedback and environmental pressures for 6000 HII regions across 19 nearby spiral galaxies

A. T. Barnes; S. C. O. Glover; K. Kreckel; E. C. Ostriker; F. Bigiel; F. Belfiore; I. Bešlić; G. A. Blanc; M. Chevance; D. A. Dale; O. Egorov; C. Eibensteiner; E. Emsellem; K. Grasha; B. A. Groves; R. S. Klessen; J. M. D. Kruijssen; A. K. Leroy; S. N. Longmore; L. Lopez; R. McElroy; S. E. Meidt; E. J. Murphy; E. Rosolowsky; T. Saito; F. Santoro; E. Schinnerer; A. Schruba; J. Sun; E. J. Watkins; T. G. Williams

doi:10.1093/mnras/stab2958

paper

Comparing the pre-SNe feedback and environmental pressures for 6000 HII regions across 19 nearby spiral galaxies

arXiv:2110.05492 · doi:10.1093/mnras/stab2958

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( $M_{⋆}$ /M $_{⊙}$ )= 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 ( $P_{therm}$ ), direct radiation ( $P_{rad}$ ), and mechanical wind pressure ( $P_{wind}$ ), which we compare to the confining pressure of their host environment ( $P_{de}$ ). The HII regions remain unresolved within our $\sim 50 - 100$ pc resolution observations, so we place upper ( $P_{max}$ ) and lower ( $P_{min}$ ) 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 $P_{max}$ measurements are broadly similar, and for $P_{min}$ the $P_{therm}$ is mildly dominant. We find that the majority of HII regions are over-pressured, $P_{tot} / P_{de} = (P_{therm} + P_{wind} + P_{rad}) / P_{de} > 1$ , and expanding, yet there is a small sample of compact HII regions with $P_{tot, max} / P_{de} < 1$ ( $\sim$ 1% of the sample). These mostly reside in galaxy centres ( $R_{gal} < 1$ kpc), or, specifically, environments of high gas surface density; log( $Σ_{gas} / M_{⊙} pc^{- 2}$ ) $\sim$ 2.5 (measured on kpc-scales). Lastly, we compare to a sample of literature measurements for $P_{therm}$ and $P_{rad}$ to investigate how dominant pressure term transitions over around 5dex in spatial dynamic range and 10 dex in pressure.

arXiv comment28 pages total, 16+3 figures, and 3 tables. Accepted for publication in MNRAS

Comparing the pre-SNe feedback and environmental pressures for 6000 HII regions across 19 nearby spiral galaxies

Abstract

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