The Impact of Assembly Bias on the Galaxy Content of Dark Matter Halos

Understand

We study the dependence of the galaxy content of dark matter halos on large-scale environment and halo formation time using semi-analytic galaxy models applied to the Millennium simulation.

• We analyze subsamples of halos at the extremes of these distributions and measure the occupation functions for the galaxies they host.
• We find distinct differences in these occupation functions.
• The main effect with environment is that central galaxies (and in one model also the satellites) in denser regions start populating lower-mass halos.