Speaker
Description
We compare the visual and structural properties of dwarf galaxies in ultra-deep HSC-SSP imaging of the COSMOS field with those measured from realistic HSC-like synthetic observations of dwarfs generated by two high-resolution cosmological hydrodynamical simulations - Illustris TNG50 and NewHorizon - using Sérsic profile fitting and non-parametric morphological metrics.
NewHorizon and TNG50 galaxies lie at opposite extremes of observed structural trends: NewHorizon produces diffuse, extended galaxies with shallow Sérsic indices, while TNG50 yields compact, concentrated systems with steep indices. Both simulations reproduce observed structural trends more closely at higher stellar masses (M* > 10^9.5 Msun) but fail to capture the full diversity of the observed COSMOS dwarfs at lower masses.
The distinct structural properties of NewHorizon and TNG50 galaxy populations reflect the underlying differences in their physical models, including ISM physics, star formation prescription and feedback implementation. The pronounced variations in the structural properties of simulated dwarfs in this mass regime underscores their heightened sensitivity to these processes. New observatories, such as the Vera C. Rubin Observatory and Euclid, will facilitate much more robust comparisons with simulations of low-mass galaxies, highlighting the utility of low-mass galaxies to constrain the physical mechanisms of galaxy formation and evolution and improve the galaxy evolution models implemented by simulations.
