Galaxy-Halo Connection
Galaxies are born and raised in dark matter halos, so they are tightly related to each other. Previous research has established the primary galaxy-halo connection, which is known as the stellar mass-halo mass relation (SHMR), from which we infer the necessity of supernovae feedback and AGN feedback to suppress the conversion from baryon to stars in low-mass and high-mass halos, respectively. Nowadays, people start to pursue the secondary galaxy-halo connection, and I am one of them. The ultimate question in this regard is that
Dark Matter Halo
Dark matter halos are the building blocks of our Universe, and they can be characterized from three perspectives: The temporal dimension: the assembly of dark matter halos as a function of cosmic time, which can be described by halo merger trees. The intra-halo dimension: the spatial and kinematic structures of dark matter halos, such as halo density profile, halo shape, halo spin, and substructures. The inter-halo dimension: the spatial clustering of dark matter halos.
Connect Structures across Cosmic Time
Galaxies at different redshifts are causally irrelevant but can be statistically linked together. Our strategy is to build the connection between galaxies and cosmic structures, such as dark matter halos and protoclusters, at different redshifts, and connect these structures across cosmic time using cosmological N-body simulations, which is more reliable and convergent than hydrodynamical galaxy formation simulations.
Galaxy Quenching
Galaxy quenching refers to the transition from a active star forming state to the quiescent state for galaxies. Star formation is so important because the integration of the star formation rate is the total stellar mass we can observe in our Universe. Galaxy quenching is so important because it (partially) explains why some galaxies convert their baryons to stars very inefficiently, or why the conversion process stops. Galaxies quench due to multiple reasons, and they can be empirically categorized into two types: internal quenching and external quenching.