A Comparison of Star-Formation Histories Derived from UniverseMachine and LEGA-C at $0.6 < z < 1$

Abstract

In this work, we compare star formation histories of massive (10.5 $< \log(\mathrm{M_*/M_{\odot}}) <$ 12) galaxies in the UniverseMachine model to those measured from the Large Early Galaxy Astrophysics Census (LEGA-C) at $0.6<z<1$. Following the LEGA-C study, we investigate how 50% ($t_{50}$) and 90% ($t_{90}$) formation timescales depend on total stellar mass. We find good agreement between the observed and model timescales for the star-forming population $\Delta\,t_{SF}\lesssim1\,\mathrm{Gyr}$ across the full mass range. In contrast, the observed age-mass correlation is weaker for the quiescent population compared to UniverseMachine models ($\Delta t_{Q}\lesssim2\,\mathrm{Gyr}$), especially at the high-mass end. This indicates continued star formation or additional processes in the most massive quiescent galaxies, a behavior not accounted for in the UniverseMachine model.