Revisiting HOD model assumptions: the impact of AGN feedback and assembly bias

Understand

The standard Halo Occupation Distribution (HOD) models were originally developed based on results from semi-analytic and hydrodynamical galaxy formation models.

• Those models have since progressed, in particular to include AGN feedback to match the galaxy luminosity function in a universe with the observed baryon fraction.
• AGN feedback affects the relationship between galaxy stellar mass and luminosity, in particular making the relationship non-monotonic.
• For matched number density samples, galaxies in luminosity-threshold samples occupy a different range of halo masses from those in stellar-mass-threshold samples.