Galaxy assembly bias and large-scale distribution: a comparison between IllustrisTNG and a semi-analytic model

In this work, we compare large scale structure observables for stellar mass selected samples at $z=0$, as predicted by two galaxy models, the hydrodynamical simulation IllustrisTNG and Santa-Cruz semi-analytic model (SC-SAM). Although both models have been independently calibrated to match observations, rather than each other, find good agreement between two-point clustering assembly bias signatures. The also show a qualitatively similar response of occupancy secondary halo paramaters other mass, such formation history concentration, although with some quantitative differences. Thus, our results demonstrate that galaxy-halo relationships in SC-SAM TNG are quite first order. However, areas which differ. For example, note strong correlation gas content environment TNG, is lacking SC-SAM, well differences predictions low-mass haloes. Moreover, higher-order statistics, cumulants density field, help accurately describe distribution discriminate degenerate behavior statistics. Our suggest SAMs promising cost-effective intuitive method generating mock catalogues next generation cosmological surveys.