We present an analysis of the clustering evolution of dark matter in four cold dark matter (CDM) cosmologies. We use a suite of high resolution, 17-million particle, N-body simulations which sample volumes large enough to give clustering statistics with unprecedented accuracy. We investigate a flat model with Ω 0 = 0.3, an open model also with Ω 0 = 0.3, and two models with Ω = 1, one with the standard CDM power spectrum and the other with the same power spectrum as the Ω 0 = 0.3 models. In all cases, the amplitude of primordial fluctuations is set so that the models reproduce the observed abundance of rich galaxy clusters by the present day. We compute mass two-point correlation functions and power spectra over three orders of magnitude in spatial scale and find that in all our simulations they differ significantly from those of the observed galaxy distribution, in both shape and amplitude. Thus, for any of these models to provide an acceptable representation of reality, the distribution of galaxies must be biased relative to the mass in a non-trivial, scale-dependent, fashion. In the Ω = 1 models the required bias is always greater than unity, but in the Ω 0 = 0.3 models an "antibias" is required on scales smaller than ∼ 5h −1 Mpc. The mass correlation functions in the simulations are well fit by recently published analytic models. The velocity fields are remarkably similar in all the models, whether they be characterised as bulk flows, single-particle or pairwise velocity dispersions. This similarity is a direct consequence of our adopted normalisation and runs contrary to the common belief that the amplitude of the observed galaxy velocity fields can be used to constrain the value of Ω 0 . The small-scale pairwise velocity dispersion of the dark matter is somewhat larger than recent determinations from galaxy redshift surveys, but the bulk flows predicted by our models are broadly in agreement with most available data.

We investigate the internal structure of clusters of galaxies in high‐resolution N‐body simulations of four different cosmologies. There is a higher proportion of disordered clusters in critical‐density than in low‐density universes, although the structure of relaxed clusters is very similar in each case. Crude measures of substructure, such as the shift in the position of the centre‐of‐mass as the density threshold is varied, can distinguish the two in a sample of just 20 or so clusters; it is harder to differentiate between clusters in open and flat models with the same density parameter. Most clusters are in a quasi‐steady state within the virial radius and are well‐described by the density profile of Navarro, Frenk & White.

A multidisciplinary team that is comprised of professionals from industry, academia, and law enforcement who are studying methods to locate clandestine graves has been formed in Colorado. This article describes this team, research conducted, and preliminary results directed toward identifying the most effective means of locating buried bodies.

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