Large-scale structure in COBE-normalized cold dark matter cosmogonies

We study the clustering of the mass distribution in COBE-normalized open and flat CDM models using large N-body simulations. With an age of the universe of 14 Gyr (12 Gyr) for the flat (open) models and a baryon density fixed by nucleosynthesis constraints, the observed abundance of rich galaxy clusters leads to tight constraints on the density parameter; 0.25 0.2, implies that galaxies are overabundant in clusters relative to the field. The tilted Omega_0=1 model, on the other hand, does require that galaxies be positively biased on all scales. We also compute the topology of isodensity contours in these models, obtaining theoretical predictions that are less sensitive to galaxy bias.