Supermassive black holes in galactic nuclei

We discuss the link between the observations of distant quasars and those of massive dark objects in the cores of many local galaxies. We show how the formation of early black holes gives rise to the luminosity function of high-z quasars, while it imprints into their dark local relics a related shape of the correlation between masses and galaxy velocity dispersions. We propose that in its lower section, the correlation slope will reveal the ( otherwise uncertain) strength of the feedback effects from the later quasar activity on the host galaxies.