Clustering in the Las Campanas Distant Cluster Survey

We utilize a sample of galaxy clusters at 0.35<z<0.6 drawn from the Las Campanas Distant Cluster Survey (LCDCS) to provide the first non-local constraint on the cluster-cluster spatial correlation function. The LCDCS catalog, which covers an effective area of 69 square degrees, contains over 1000 cluster candidates. Estimates of the redshift and velocity dispersion exist for all candidates, which enables construction of statistically completed, volume-limited subsamples. In this analysis we measure the angular correlation function for four such subsamples at z~0.5. After correcting for contamination, we then derive spatial correlation lengths via Limber inversion. We find that the resulting correlation lengths depend upon mass, as parameterized by the mean cluster separation, in a manner that is consistent with both local observations and CDM predictions for the clustering strength at z=0.5.