The physics we glean from the small-scale Universe

Vadim Semenov (Harvard University)

September 18, 2023

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Abstract: The first year of JWST has revealed a surprising abundance of bright galaxies in the very early universe, many of which exhibit disk morphologies and kinematics, challenging our current understanding of galaxy formation. At the same time, recent astrometric and spectroscopic surveys of nearby stars (such as Gaia, H3, LAMOST, and APOGEE) provided us with a view of our own Milky Way assembly, suggesting that the Milky Way disk also formed surprisingly early, within the first 1–2 Gyr of evolution. Tackling galaxy formation in these extreme unexplored regimes requires simulations with predictive modeling of unresolved star formation and feedback. I will present results from such simulations, where star formation and feedback are tightly coupled with the turbulent ISM dynamics. These simulations help us understand the origin of inefficient star formation on >kpc scales and provide us with a simple physical framework connecting global star formation with the processes operating on the scales of individual star-forming regions that can be used to investigate star and galaxy formation across cosmic time. I will also show insights from large-scale cosmological simulations that shed new light on the early formation of galactic disks like our own Milky Way.