A Physical Model for the joint evolution of QSOs and Spheroids

We summarize our detailed, physically grounded, model for the early co-evolution of spheroidal galaxies and of active nuclei at their centers (astro-ph/0307202). Our predictions are excellent agreement with observations for a number of observables which proved to be extremely challenging for all the current semi-analytic models, including the sub-mm counts and the corresponding redshift distributions, and the epoch-dependent K-band luminosity function of spheroidal galaxies. Also, the black hole mass function and the relationship between the black hole mass and the velocity dispersion in the galaxy are nicely reproduced.