Primordial inhomogeneities in the expanding universe. II. General features of spherical models at late times

We study the density profile that forms around a spherically symmetric bound central core immersed in a homogeneous background k=0 or k=-1 Friedmann-Robertson-Walker cosmological model, with zero pressure. Although the density profile in the linearized regime is almost arbitrary, in the nonlinear regime we obtain certain universal features of the density profile that are independent of the details of the initial conditions. We discuss the formation of ''halos'' (''holes'') with densities greater than (less than) the average cosmological density. We are able to show that in most region ''halos'' form, and we obtain universal values for the slope of the ln (density) --ln (radius) profile in those ''halos'' at late times, independently of the shape of the initial density profile. We derive restriction on where it is possible for ''holes'' to exist at late times, and on how such ''holes'' must have evolved