A catalogue of galaxy cluster models

We present a technique to construct a fair sample of simulated galaxyclusters, and build such a sample for a specific cosmological structureformation scenario. Conventionally one extracts such a sample from a singlelow-resolution large-scale simulation. Here we simulate the clustersindividually at high resolution. We construct a model catalogue selected onexpected final cluster mass. Such a catalogue will not have a well-definedrichness limit, because the relation between richness and mass is fairly broad.However, by applying the appropriate completeness corrections, the results forthe mass-selected catalogue can be compared with observations forrichness-selected cluster catalogues. We build a model cluster catalogue forthe Omega_0=1 CDM scenario that is designed to mimic the ENACS sample of richAbell clusters. We use the distribution of richness, corrected forincompleteness, to fix the present epoch. We find sigma_8=0.4-0.5, which isconsistent with other determinations. The catalogue is 70 per cent complete fora richness larger than 50, but we do have a complete subsample for a richnesslimit of 75. As a first test we compare the cumulative distribution ofline-of-sight velocity dispersions to those found for several observationalsamples, and find that they match best for a value of around 0.4 for sigma_8.This means that we find consistent values for sigma_8 for the CDM Omega_0=1scenario on cluster scales.