Dynamical and Photometric Imprints of Feedback Processes on the Formation and Evolution of E/S0 Galaxies

We show that the observed velocity dispersion function of E/S0 galaxies matches strikingly well the distribution function of virial velocities of massive halos virializing at z ≥ 1.5, as predicted by the standard hierarchical clustering scenario in a ΛCDM cosmology, for a constant ratio σ/ V vir ≃ 0.55 ± 0.05, which is close to the value expected at virialization if it typically occurred at z ≳ 3. This strongly suggests that dissipative processes and later merging events had little impact on the matter density profile. Adopting the above σ/ V vir ratio, the observed relationships between photometric and dynamical properties that define the fundamental plane of elliptical galaxies, such as the luminosity-σ (Faber-Jackson) and the luminosity-effective radius relations, as well as the M BH -σ relation, are nicely reproduced. Their shapes turn out to be determined by the mutual feedback of star formation (and supernova explosions) and nuclear activity, along the lines discussed by Granato and coworkers. To our knowledge, this is the first semianalytic model for which simultaneous fits of the fundamental plane relations and of the epoch-dependent luminosity function of spheroidal galaxies have been presented.