Protoclusters in cosmological hydrodynamical simulations: properties of galaxies and the forming intracluster medium
Abstract: The study of protoclusters at cosmic noon is crucial for understanding how the environment and transformational processes, which peak in activity around this epoch, influence the evolution of cluster galaxies and the formation of the intracluster medium (ICM). From an observational perspective, the combination of diverse methods for searching protoclusters in the high-redshift Universe, along with the limited statistics of current protocluster galaxy samples, complicates our understanding of galaxy evolution in these extreme environments. In this context, theoretical models can help enhance our understanding of early cluster galaxy evolution. In particular, cosmological hydrodynamical simulations enable self-consistent modeling of gas dynamics and astrophysical processes within a cosmological framework. In this seminar, I will present predictions from the latest version of the DIANOGA cosmological hydrodynamical simulations of galaxy clusters, focusing on the properties of galaxy populations at z ∼ 2, right before the first virialized clusters emerge from the cosmic web. I will explore how properties such as the star-forming main sequence, the galaxy stellar mass function, gas reservoirs, and the fraction of quenched galaxies depend on both local and global environments. To do this, I will also compare the DIANOGA protoclusters with a simulation of an average volume of the Universe, representative of the "field" . I will show how the overdense environment leaves a distinct signature on the galaxy population in the extreme environments of cluster progenitors already at z ∼ 2. Additionally, I will present the evolution of the thermodynamic properties of the diffuse gas in massive halos across the protocluster-to-cluster transition, correlating these properties with past star formation and AGN activity to highlight the role of these processes in heating and pressurizing the ICM.