STScI Preprint #1244

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 multi-band 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 broad band optical imaging and spectroscopy with the Low Resolution Imaging Spectrograph at the 10 meter W. M. Keck Observatory telescope; K-band imaging with IRIM at the 4 meter Kitt Peak National Observatory telescope; and deep, high angular resolution imaging with the WFPC2 onboard 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 2D optical high-z cluster searches.

Status:

Appeared in: The Astronomical Journal, 116:549-559, 1998

Affiliations:

¹)Palomar Observatory, California Institute of Technology, Pasadena, CA 91125
²)Dominion Astrophysical Observatory, 5071 W. Saanich Road, Victoria, BC V8X 4M6
³) Space Telescope Science Institute⁷, 3700 San Martin Drive, Baltimore, MD 21218
⁴)Observatories of the Carnegie Institution of Washington, 813 Santa Barbara Street, Pasadena, CA 91101
⁵) Hubble Fellow
⁶) Present Address : Palomar Observatory, California Institute of Technology, Mail Stop 105-24, Pasadena, CA 91125
⁷)Space Telescope Science Institute is operated by the Association of Universities for Research in Astronomy, Inc., under contract to the National Aeronautics and Space Administration.