LARGE-SCALE STRUCTURE IN THE UNIVERSE

Models containing the essential features of the adiabatic theory of galaxy formation are investigated, A cellular structure of uniform two-dimensional sheets of galaxies, with voids in between, is found to provide a natural explanation for the discrepancy between the observed clustering length (where the two-point correlation function is unity) and the expected scale of large-scale structure in a universe dominated by light neutrinos. The model also accounts for certain features in the Durham-AAT redshift survey (Shanks et al. 1983). An analysis of the growth of surface density perturbations within expanding two-dimensional 'pancakes' is shown to lead to structure on scales up to the scale of galaxy clusters, provided that galaxies are formed by local fragmentation of pancakes, and the pancaking epoch is rather early (zp^3). The growth rates computed suggest that published Af-body simulations have too few particles per cell to be able to model the galaxy correlation function accurately after the pancaking epoch. The pancake theory, therefore, should not be rejected on the grounds that matching the observed correlation function with that of N-body simulations after pancaking implies zp © Royal Astronomical Society.