Monday

Galaxy clusters are excellent probes to study the effect of dense environments on galaxy formation and evolution. Along with high-quality observational data, accurate cosmological simulations are required to improve our understanding of galaxy evolution in these systems. As the simulations are conventionally calibrated to match the local Universe, it is crucial to check their validity at intermediate and high redshifts before using their predictions to interpret observations at these epochs. We compare state-of-the-art observational data of massive galaxy clusters at different redshifts between 1.5 and 0 with predictions from the Hydrangea suite, a set of 24 cosmological hydrodynamic simulations of massive galaxy clusters that is part of the C-EAGLE project. We focus on three fundamental observables of galaxy clusters to carefully verify the total stellar content and its distributions in the simulated clusters: the total stellar-to-halo mass ratio, the stellar mass function (SMF), and the radial mass density profile of the cluster galaxies. I will present the results from this comparison, and demonstrate that the simulations can be used both to connect observations from different redshifts and to study the physical processes that affect the cluster galaxies over cosmic time. However, we also see some differences between the simulations and observations. I will discuss possible reasons behind the discrepancies, and how they might be overcome in future simulations. If time permits, I will also present results from ongoing work to predict stellar mass functions in galaxy (proto-)clusters at even higher redshifts, which will be tested by JWST and Euclid in the near future.