Manuel Arca Sedda (University of Rome La Sapienza, Italy)
In this contribution we discuss how the centres of galaxy clusters evolve in time, showing the results of a series of direct N-body modelling at high resolution. In particular, we followed the evolution of a galaxy cluster with a mass of around 10^14 solar masses in four different configurations: 1) isolated cluster; 2) cluster subjected to the action of Dark Energy; 3) cluster composed of galaxies and gas; 4) cluster composed of galaxies and gas subjected to the action of Dark Energy. The dynamical evolution of the system leads in all the cases to the formation of dense and massive substructures in the cluster centre, whose properties depend slightly on the kind of environment in which the cluster evolve. Indeed, these substructures form in consequence of a series of collisions and merging among the galaxies that move in the innermost region of the cluster under the action of the dynamical friction. In our contribution, we investigate how the structural properties of the merging product depends on the main characteristics of those galaxies that contributed to its formation and, moreover, to the effects induced by the environment in which the cluster evolves.