Kavli Affiliate: Risa H. Wechsler
| First 5 Authors: Jenny T. Wan, Jenny T. Wan, , ,
| Summary:
The advent of JWST has revolutionized the study of faint satellite galaxies
at $z gtrsim 1$, enabling statistical constraints on galaxy evolution and the
galaxy$-$halo connection in a previously unexplored mass and redshift regime.
We compare satellite abundances at $1 < z < 3.5$ from recent JWST observations
with predictions from cosmological dark matter-only zoom-in simulations. We
identify and quantify several sources of biases that can impact theoretical
satellite counts, finding that assumptions about subhalo tidal evolution
introduce the largest uncertainty in predictions for the satellite mass
function. Using a flexible galaxy disruption model, we explore a range of
disruption scenarios, spanning hydrodynamically motivated and idealized
prescriptions, to bracket plausible physical outcomes. We show that varying
galaxy durability can change the predicted satellite mass functions by a factor
of $sim3.5$. The JWST data and our fiducial model are consistent within
$1-2sigma$ across the full redshift ($1 < z < 3.5$) and stellar mass
($M_star> 10^7~mathrmM_odot$) range probed. We find evidence that subhalos
are at least as long-lived as predicted by hydrodynamic simulations. Our
framework will enable robust constraints on the tidal evolution of subhalos
with future observations. This work presents the first direct comparison
between cosmological models and observations of the high-redshift satellite
population in this low-mass regime. These results showcase JWST’s emerging
power to test structure formation in the first half of the Universe in a new
domain and to constrain the physical processes driving the evolution of
low-mass galaxies across cosmic time.
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