Contributed Talk - Splinter Computation

Friday, 25 September 2020, 09:02   (virtual room B)

Empirically Motivated Feedback in Galaxy Formation

Benjamin Keller, J.M. Diederik Kruijssen, Mélanie Chevance
Ruprecht-Karls-Universität Heidelberg

To explain the long global molecular depletion times observed in galaxies, GMCs must be held up by non-thermal support for long time scales, or be disrupted by feedback on short ones, before a significant fraction of their mass forms stars. State-of-the-art statistical analysis of high resolution CO+optical observations (Kruijssen+ 2018, 2019; Chevance+ 2019) is now finally able to resolve this problem and constrain the details of the time and length scales of the GMC life cycle, suggesting that the feedback-regulated picture is the correct one. However, it is non-trivial to translate these observations into fundamental, physical input parameters for the stellar feedback models used in numerical simulations of galaxy formation and evolution. In this contribution, I will show how we can use these observationally-derived quantities to determine the impact of stellar feedback and develop a sub-grid model for stellar feedback that matches these observational constraints. This empirically motivated feedback model allows us to sidestep the uncertain physics and unresolved structure involved in the interaction of stellar winds, HII regions, and radiation pressure and instead simply match quantities measured for real GMCs. I will show results of how this feedback model changes the ISM, stellar population, and outflow behaviour in both isolated and cosmological disc galaxies, compared to the impact of supernovae alone, or to using SNe feedback in conjunction with a simple model for stellar winds.