The palomar distant cluster survey .1. The cluster catalog

We present an optical/near-IR selected catalog of 79 clusters distributed over an area of 5.1 degrees sq. The catalog was constructed from images obtained with the 4-Shooter CCD mosaic camera on the Hale 5 m telescope operating in ''scan'' mode. The survey, hereafter known as the Palomar distant cluster survey (PDCS), was conducted in two broadband filters that closely resemble V and I. The 4 sigma limiting magnitudes for our 300 s exposures are similar to 23.8 (V) and 22.5 (I). A matched filter algorithm was developed and employed to identify the cluster candidates by using positional and photometric data simultaneously. The clusters cover the range 0.2 less than or equal to z less than or equal to 1.2, based on the redshift estimates derived in the cluster detection procedure. An accurate selection function is generated from extensive simulations. We find that the cumulative surface density of clusters with richness class R greater than or equal to 1 is about a factor of 5 higher than the extrapolated density of R greater than or equal to 1 Abell clusters. The PDCS results are consistent with a constant comoving density of clusters to z less than or equal to 0.6, albeit at the above high density level. Constraints on cluster abundances at z>0.6 will be possible with the acquisition of spectroscopic redshifts for a large subset of these cluster candidates. We also present a supplemental catalog of 28 clusters that do not satisfy all our selection criteria but which include some of the most distant systems detected in the survey. Finding charts for all 107 cluster candidates are provided. (C) 1996 American Astronomical Society.