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

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 H II regions identified from the PHANGS-MUSE survey of 19 nearby (< 20Mpc) 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 H II regions, which we use to investigate their internal pressure terms. We estimate the photoionised gas (Ptherm), direct radiation (Prad), and mechanical wind pressure (Pwind), which we compare to the confining pressure of their host environment (Pde). The H II regions remain unresolved within our ∼50−100 pc resolution observations, sowe place upper (Pmax) and lower (Pmin) limits on each of the pressures by using aminimum (i.e. clumpy structure) and maximum (i.e. smooth structure) size, respectively. We find that the Pmax measurements are broadly similar, and for Pmin the Ptherm is mildly dominant. We find that the majority of H II regions are over-pressured, Ptot/Pde = (Ptherm+Pwind+Prad)/Pde > 1, and expanding, yet there is a small sample of compact H II regionswith Ptot,max/Pde < 1 (∼ 1%of the sample). Thesemostly reside in galaxy centres (Rgal < 1 kpc), or, specifically, environments of high gas surface density; log(Σgas/M pc−2)∼2.5 (measured on kpc-scales). Lastly, we compare to a sample of literature measurements for Ptherm and Prad to investigate how dominant pressure term transitions over around 5 dex in spatial dynamic range and 10 dex in pressure.