luminosity function

I worked on the galaxy evolution synthesis this morning. I think I decided that predictions of the galaxy luminosity function are too dependent on ad-hoc models of star formation and feedback for the luminosity function itself to provide a good test of the CDM model. In principle, the observed luminosity function and the theoretical mass function from CDM (for DM halos) produces a prediction for the Tully–Fisher relation (see recent work by Blanton and Geha) or the fundamental plane, but it seems that even this is loose in the sense that a departure or violation would be viewed by very few as evidence against the fundamental assumptions of CDM. It would be viewed as evidence that dark matter and stars can have different velocity dispersions (which would by no means present any paradox). Maybe with the addition of weak lensing (galaxy–galaxy) constraints it would become a falsifiable prediction of the fundamental CDM model.