Momentum feedback from marginally resolved H ii regions in isolated disc galaxies

Abstract

We present a novel, physically-motivated sub-grid model for HII region feedback within the moving mesh code Arepo, accounting for both the radiation pressure-driven and thermal expansion of the ionised gas surrounding young stellar clusters. We apply this framework to isolated disc galaxy simulations with mass resolutions between 103 M⊙ and 105 M⊙ per gas cell. Each simulation accounts for the self-gravity of the gas, the momentum and thermal energy from supernovae, the injection of mass by stellar winds, and the non-equilibrium chemistry of hydrogen, carbon and oxygen. We reduce the resolution-dependence of our model by grouping those HII regions with overlapping ionisation front radii. The Strömgren radii of the grouped HII regions are at best marginally-resolved, so that the injection of purely-thermal energy within these radii has no effect on the interstellar medium. By contrast, the injection of momentum increases the fraction of cold and molecular gas by more than 50 per cent at mass resolutions of 103 M⊙, and decreases its turbulent velocity dispersion by ∼10 kms−1. The mass-loading of galactic outflows is decreased by an order of magnitude. The characteristic lifetime of the least-massive molecular clouds ($M/{\rm M}_\odot \lesssim 5.6 \times 10^4$) is reduced from ∼18 Myr to $\lesssim 10$ Myr, indicating that HII region feedback is effective in destroying these clouds. Conversely, the lifetimes of intermediate-mass clouds ($5.6 \times 10^4 \lesssim M/{\rm M}_\odot \lesssim 5 \times 10^5$) are elongated by ∼7 Myr, likely due to a reduction in supernova clustering. The derived cloud lifetimes span the range from 10-40 Myr, in agreement with observations. All results are independent of whether the momentum is injected from a spherical or a blister-type HII region.

Linking stellar populations to H II regions across nearby galaxies

“…Recent simulations (e.g. Dale et al 2012Dale et al , 2013Raskutti et al 2016;Gatto et al 2017;Rahner et al 2017Rahner et al , 2019Kim et al 2018Kim et al , 2021aKannan et al 2020;Jeffreson et al 2021) and observational evidence (e.g. Grasha et al 2018Grasha et al , 2019Kruijssen et al 2019;Chevance et al 2020a,b;Kim et al 2021b;McLeod et al 2021;Barrera-Ballesteros et al 2021a,b;Hannon et al 2019Hannon et al , 2022 suggest that, in particular, feedback in the early, pre-supernovae (pre-SNe) stages of high-mass stars (i.e.…”

WISDOM project -- XI. Star Formation Efficiency in the Bulge of the AGN-host Galaxy NGC 3169 with SITELLE and ALMA

“…Kruijssen et al 2019b;Chevance et al 2020;Ward et al 2020;Zabel et al 2020;Kim et al 2021;Chevance et al 2022), as well as for numerical simulations (e.g. Fujimoto et al 2019;Jeffreson et al 2021).…”

Linking stellar populations to HII regions across nearby galaxies: I. Constraining pre-supernova feedback from young clusters in NGC1672

“…Recent simulations (e.g. Dale et al 2012Dale et al , 2013Raskutti et al 2016;Gatto et al 2017;Rahner et al 2017Rahner et al , 2019Kim et al 2018Kim et al , 2021bKannan et al 2020;Jeffreson et al 2021) and observational evidence (e.g. Grasha et al 2018Grasha et al , 2019Kruijssen et al 2019a;Chevance et al 2020b,a;Kim et al 2021a;McLeod et al 2021;Barrera-Ballesteros et al 2021b,a;Hannon et al 2019Hannon et al , 2022 suggest that, in particular, feedback in the early (pre-SNe) stages of high-mass stars (i.e.…”