The code is designed for large cosmological simulations and incorporates a number of ideas which improve the code's efficiency both in terms of speed of execution and memory use. A simulation containing particles each of dark matter and gas can be run in roughly three days on a 250Mhz DEC Alpha workstation. This Grand Challenge project is using the 512 node Cray T3D in Edinburgh and more recently the Cray T3E at MPI, Garching. Several particle collisionless runs and particle gas runs have been completed. They simulated a dense cluster field and a field dominated by a large filament.
Strong filaments appear between nearby peaks whose tidal tensors are nearly aligned.
Their results indicate that lensing at moderate redshift can probe the filaments best among these three observational strategies, but also that the SZ effect will be useful for probing the outskirts of clusters. They constructed number counts as a function of magnitude for each cluster and for each colour. The luminosity functions of both clusters were well described by a Gaussian function for the bright galaxies, combined with a Schechter function at the faint end, similar to that required to fit the luminosity function in local clusters. The slope at the faint end of the Schechter function in both clusters was extremely steep in V . A shallower slope was seen to the limit of the I data, indicating that the cluster population was rapidly bluing at fainter magnitude.