The central structure of Intra-Cluster Medium: recent encouraging results from simulations.

I will briefly recall the thermodynamic properties of hot gas in the central region of galaxy clusters, and the problems encountered in reproducing them by means of cosmological hydrodynamical simulations. Then I will present recent results obtained by our numerical group in this field. For the first time, we obtain a relatively large sample of simulated clusters characterized by a good match with observation. In particular we get a satisfactory mixture of cool core and non-cool core clusters. The key physical ingredients responsible for this success will be discussed.