halo occupation

It was a low-research day again, but Berlind gave a nice seminar on the motivation for, execution of, and results from halo-occupation analyses of large-scale structure, in which the problem is separated into a dark-matter calculation (the positions and masses of virialized haloes) and a separate galaxy astrophysics question (how do galaxies occupy haloes with particular properties). As far as I am concerned, the big benefit of the halo occupation formalism is that it allows you to straightforwardly marginalize over galaxy gastrophysics issues when performing cosmological tests at intermediate and small scales. But as Berlind pointed out, it can be very informative about possible galaxy astrophysics issues when there are discrepancies between an observation and a model prediction. He gave a nice example: a straightforward halo occupation analysis of Masjedi's small-scale clustering result shows that galaxies are not distributed in dense structures according to the standard Navarro-Frenk-White prescription.