Witnessing Galaxy-SMBH Co-Evolution at Redshift ~ 2

In a recent multiwavelength study of galaxies at redshift ~ 2 by Daddi et al. (2007a,b) it is shown that galaxies with a Mid-IR excess most likely harbor a Compton-thick AGN, thus bringing to about 1/3 the fraction of z ~ 2 galaxies hosting an AGN. This finding opens a number of intriguing issues concerning the concomitant growth of galaxies and supermassive black holes, AGN feedback, and downsizing, at the cosmic epoch of most intense star formation and nuclear activity.