THE OBSERVATIONAL PROPERTIES OF AN OMEGA = 0.2 COLD DARK MATTER UNIVERSE

We have carried out a detailed investigation of the observational properties of an OMEGA = 0.2 cold dark matter universe in which galaxies are assumed to trace the dark matter distribution. We choose to examine this particular case as it is a representative example of a class of low-density CDM models which are currently receiving widespread attention. We have calculated the two-point correlation function, the reduced three-point function, velocity moments, galaxy group statistics, the distribution of clusters and voids and the variance, sigma2, of galaxy counts in cells. We find that the low-density model provides as good a match to observations as the 'standard' OMEGA = 1 CDM model on scales between 1 and 20 h-1 Mpc. On smaller scales, the assumption that mass traces tight does not give such good agreement with the data. We find that galaxies are somewhat too strongly clustered to match observations. On larger scales, the low-density model matches the clustering significantly better than standard CDM. Bearing in mind that complex hydrodynamical effects are likely to affect the distribution of galaxies on small scales, we conclude that a low-density CDM model may well prove to be an acceptable scenario for the formation of the large-scale structure we see today .