PERTURBATION OF COHERENT LARGE-SCALE STRUCTURE

Linear perturbation theory on the background of a one-dimensional, non-linear inhomogeneous universe, described by the Zeldovich solution, is considered. Special attention is paid to perturbations inside the 'wall'-like structures, for which the exact solution is given for an Einstein-de Sitter behaviour of the scale factor. The non-linear effect of the density inhomogeneity on the evolution of the peculiar velocity is written in the form of a relation between the peculiar velocity and the density parameter-OMEGA including the correction due to the density contrast delta-0 of the Zeldovich solution. It is shown that the component parallel to the walls is characterized by OMEGA-0.6 (1 + delta-0)-0.57, whereas the background component perpendicular to the walls obeys the same relation as that in the homogeneous and isotropic background in spite of its fully non-linear property. We also give an exact solution for one-dimensional perturbations perpendicular to the walls.