Friday, September 19, 2025 at 12:15 pm

JILA Foothills Room

Jenny Wan, Stanford University

"Dwarf Galaxies at Cosmic Noon:  New JWST Constraints on Satellite Models and Subhalo Tidal Evolution "

Abstract:

Abstract: The advent of JWST has revolutionized the study of faint satellite galaxies z > 1, enabling statistical constraints on galaxy evolution and the galaxy--halo connection in a previously unexplored mass and redshift regime. I will present a comparison between satellite abundances measured from JWST observations at 1 < z < 3.5 against predictions from cosmological dark matter-only zoom-in simulations. A key challenge is that theoretical predictions depend sensitively on how we model subhalo tidal evolution. Using a flexible galaxy disruption framework, we explore a wide range of scenarios and show that varying assumptions about galaxy durability can shift the predicted satellite mass function by more than a factor of three. Despite this uncertainty, the JWST data and our fiducial model agree well across the full redshift and mass range (M* > 107 Msun) probed. These results suggest that subhalos are at least as long-lived as predicted by hydrodynamic simulations, and showcase JWST's unique ability to constrain the physics of low-mass galaxy evolution and structure formation in the early Universe.

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