Most disc galaxies go through an early epoch of being "gas rich," an era that is now actively explored through ALMA and JWST observations. This high gas-fraction phase got going much sooner (z > 3) than anticipated by cosmological N-body simulations. A new class of controlled (Nexus) simulations of these early times reveals that turbulent discs have extraordinary properties. Unexpectedly, spiral arms, stellar and gaseous bars, even bulges, all form under these conditions. Moreover, baryon sloshing in 3D driven by strong feedback gives rise to thickened stellar discs. We argue this is the most likely origin of alpha-enriched thick stellar discs observed today, and that discs are not born thick, as previously claimed. The sloshing gives rise to specific signatures that are observable in ALMA data. We discuss the implications of the new work on galaxy studies.
Gas-rich discs in the early universe : clues to the Milky Way’s origins
Lundi 27 octobre 2025
de
14:00 à
15:00
Room 108, Building Les communs
