A Study of Nine High-Redshift Clusters of Galaxies. I. The Survey

We present a description of the observations and data reduction procedures for an extensive spectroscopic and multiband photometric study of nine high-redshift, optically selected cluster candidates. The primary goal of the survey is to establish new constraints on cluster and galaxy evolution, with specific emphasis on the evolution of galaxy morphology and on the star formation history of the galaxies within and around distant clusters. We have measured 892 new redshifts for galaxies with R ≤ 23.3. The data will also serve as deep probes of the foreground and background large-scale structures. The observations include broadband optical imaging and spectroscopy with the Low Resolution Imaging Spectrograph at the 10 m W. M. Keck Observatory telescope; K-band imaging with the IRIM camera at the 4 m Kitt Peak National Observatory telescope; and deep, high angular resolution imaging with the Wide Field Planetary Camera 2 on board the Hubble Space Telescope. We also describe the procedures used to obtain morphological information. We have established that six of the nine cluster candidates are indeed real space density enhancements and are representative of those typically associated with clusters of galaxies. The remaining three candidates appear to be projections of several smaller groups at widely separated distances. This success rate is consistent with estimates of the false-positive rate in two-dimensional optical high-z cluster searches.