Exploring the halo occupation of AGN using dark-matter cosmological
  simulations
  A semi-empirical model is presented that describes the distribution of Active
Galactic Nuclei (AGN) on the cosmic web. It populates dark-matter halos in
N-body simulations (MultiDark) with galaxy stellar masses using empirical
relations based on abundance matching techniques, and then paints accretion
events on these galaxies using state-of-the-art measurements of the AGN
occupation of galaxies. The explicit assumption is that the large-scale
distribution of AGN is independent of the physics of black-hole fueling. The
model is shown to be consistent with current measurements of the two-point
correlation function of AGN samples. It is then used to make inferences on the
halo occupation of the AGN population. Mock AGN are found in halos with a broad
distribution of masses with a mode of $\approx 10^{12}\,h^{-1} \, M_{\odot}$
and a tail extending to cluster-size halos. The clustering properties of the
model AGN depend only weakly on accretion luminosity and redshift. The fraction
of satellite AGN in the model increases steeply toward more massive halos, in
contrast with some recent observational results. This discrepancy, if
confirmed, could point to a dependence of the halo occupation of AGN on the
physics of black-hole fueling.
