THE LARGE-SCALE STRUCTURE OF THE UNIVERSE

Stefano Borgani

INFN - Sezione di Trieste, c/o Dipartimento di Astronomia,
via Tiepolo 11, I-34131 Trieste, Italy

Abstract:

In these Lectures I provide general notions about the formation and evolutions of cosmic structures, like galaxies and clusters of galaxies, within the standard cosmological scenario, based on a spatially homogeneous and isotropic expanding Universe. After briefly reviewing the cinematics and dynamics of the Friedman-Robertson-Walker model, I introduce the notation for describing the degree of inhomogeneity which characterizes the structure of the Universe on scales $\sim 100$ Mpc, thus much smaller than the cosmological event horizon ($\sim 5000$ Mpc). Afterwards I introduce the basic equations for the evolution of density perturbations and derive their solution in the linear case of small perturbations. In this context, I also describe the evolution of perturbations both in the baryonic and in the non-baryonic dark matter (DM) component. We explicitely show how the nature (either cold or hot) of the DM affects the formation and evolution of cosmic structures. We finally discuss how modern numerical computational techniques and observations can be joined together to improve our understanding of the nature of our Universe and its evolution,