A model for cosmological simulations of galaxy formation physics
  We present a new comprehensive model of the physics of galaxy formation
designed for large-scale hydrodynamical simulations of structure formation
using the moving mesh code AREPO. Our model includes primordial and metal line
cooling with self-shielding corrections, stellar evolution and feedback
processes, gas recycling, chemical enrichment, a novel subgrid model for the
metal loading of outflows, black hole (BH) seeding, BH growth and merging
procedures, quasar- and radio-mode feedback, and a prescription for radiative
electro-magnetic (EM) feedback from active galactic nuclei (AGN). The metal
mass loading of outflows can be adjusted independently of the wind mass
loading. This is required to simultaneously reproduce the stellar mass content
of low mass haloes and their gas oxygen abundances. Radiative EM AGN feedback
is implemented assuming an average spectral energy distribution and a
luminosity-dependent scaling of obscuration effects. This form of feedback
suppresses star formation more efficiently than continuous thermal quasar-mode
feedback alone, but is less efficient than mechanical radio-mode feedback in
regulating star formation in massive haloes. We contrast simulation predictions
for different variants of our galaxy formation model with key observations. Our
best match model reproduces, among other things, the cosmic star formation
history, the stellar mass function, the stellar mass - halo mass relation, g-,
r-, i-, z-band SDSS galaxy luminosity functions, and the Tully-Fisher relation.
We can achieve this success only if we invoke very strong forms of stellar and
AGN feedback such that star formation is adequately reduced in both low and
high mass systems. In particular, the strength of radio-mode feedback needs to
be increased significantly compared to previous studies to suppress efficient
cooling in massive, metal-enriched haloes.
