we have seen previously, the correlations between the black hole mass and the photometric or dynamical properties of the host galaxy suggest that the former grows as the latter is assembled. The different physical processes involved on the growth of black holes inside galaxies require a numerical treatment or, in other words, an appeal to cosmological simulations. In fact, there are different reasons justifying such an approach: first, because a significant volume of the universe can be probed; second, because the dynamics of dark matter and the hydrodynamics of the gas, including physical processes like heating, cooling, ionization of different elements can be taken into account self consistently. Moreover, it is possible to study environmental effects on the galaxies themselves as well as the chemical evolution of the interstellar and of the intergalactic gas, including the effects of supernovae and turbulent diffusion of heavy metals. The simulations permit to test star formation recipes, models for the growth of seeds and to investigate the influence of black holes on the environment when they are in an active phase.

Cosmological Simulations
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The results described in this section were all derived from simulations performed at the Observatoire de la Côte d’Azur (Nice) 