Nonlinear evolution of large-scale structure in the universe

A series of 1000-body simulations have been performed in order to study the nonlinear evolution of large-scale structure in an Einstein-de Sitter universe. Simulations in which particles are initially distributed independently are compared with simulations in which a flat spectrum of random waves is truncated on small scales. The former simulations model hierarchical clustering from white noise initial conditions while the latter represent the growth of structure in the pancake model. The Poisson simulations form tight clusters with no large-scale coherence whereas the pancake simulations produce long chains. The correlation function in the Poisson simulation grows in a self-similar fashion and is not well fitted by a power law, whereas in the pancake models it has roughly power law behavior over the range 100-1 with a slope that increases with time. The pancake models fit the filamentary structure of the observed galaxy distribution considerably better than the Poisson models.