Galaxy formation is broadly a competition between two effects: gravity, which collapses material down to smaller scales; and "feedback", which injects energy from these small scales to eject material out to larger scales. Modelling the impact of energy released by massive stars ("stellar feedback") has long been a "holy grail" problem of numerical studies of galaxy formation.
Numerous approaches have been proposed over the decades, and the field has in general made steady progress since the first attempts to model dissipational galaxy formation with simulations. Despite this progress, there still remains tremendous uncertainty on both the underlying physics of stellar feedback, and how this physics can be captured in "sub-grid" models. Further complicating this problem is the degeneracy issue that can arise when very different models produce comparable results, within observational uncertainties.
In this talk, I will show how new approaches in applying observational insight and a careful examination of the underlying physical processes involved in stellar feedback can improve the fidelity of simulations of galaxy formation. With these new approaches, we can better understand the "baryon cycle" of galaxies, which connects the gas within and around galaxies to the stars they contain. I conclude with a cautionary discussion on the uncertainties that underlie our simulation models, and what it really means to "simulate" an astrophysical system.
This Friday colloquium will be entirely online. Attendees can therefore participate either in-person or via Zoom. Please join via Zoom at
https://uio.zoom.us/j/69001043754?pwd=cEJpbVE5ci9PdWNtRld2TDNNcGtKdz09
Meeting ID:690 0104 3754
Passcode: PeiseStua3
Attendees will be muted during the colloquium, but will have the opportunity to ask questions at the end by clicking on the "raise hand” button (or send a request via chat).