EDisCS – the ESO distant cluster survey

Sample definition and optical photometry

¹ Max-Planck-Institut für Astrophysik, Karl-Schwarschild-Str. 1, Postfach 1317, 85741 Garching, Germany e-mail: swhite@mpa-garching.mpg.de
² Steward Observatory, University of Arizona, 933 North Cherry Avenue, Tucson, AZ 85721, USA
³ Herzberg Institute of Astrophysics, National Research Council of Canada, Victoria, BC V9E 2E7, Canada
⁴ School of Physics and Astronomy, University of Nottingham, University Park, Nottingham NG7 2RD, UK
⁵ Max-Planck Institut für extraterrestrische Physik, Giessenbachstrasse, 85748 Garching, Germany
⁶ Institute for Astronomy, Royal Observatory Edinburgh, Blackford Hill, Edinburgh EH9 3HJ, UK
⁷ Department of Physics, Bristol University, H. H. Wills Laboratory, Tyndall Avenue, Bristol BS8 ITL, USA
⁸ Astronomy Department, University of Washington, Box 351580, Seattle, WA 98195, USA
⁹ LERMA, UMR8112, Observatoire de Paris, section de Meudon, 5 Place Jules Janssen, 92195 Meudon Cedex, France
¹⁰ Institut d'Astrophysique de Paris, 98 bis boulevard Arago, 75014 Paris, France
¹¹ Institut für Astrophysik, Friedrich-Hund-Platz 1, 37077 Goettingen, Germany
¹² GEPI, CNRS-UMR8111, Observatoire de Paris, section de Meudon, 5 Place Jules Janssen, 92195 Meudon Cedex, France
¹³ Laboratoire d'Astrophysique, UMR 5572, Observatoire Midi-Pyrenées, 14 Avenue E. Belin, 31400 Toulouse, France
¹⁴ Osservatorio Astronomico, vicolo dell'Osservatorio 5, 35122 Padova, Italy
¹⁵ Sterrewacht Leiden, PO Box 9513, 2300 RA, Leiden, The Netherlands
¹⁶ Institut für Astrophysik und Extraterrestrische Forschung, Universität Bonn, Auf dem Hügel 71, 53121 Bonn, Germany

Received: 24 September 2004
Accepted: 28 July 2005

Abstract

We present the ESO Distant Cluster Survey (EDisCS), a survey of 20 fields containing distant galaxy clusters with redshifts ranging from 0.4 to almost 1.0. Candidate clusters were chosen from among the brightest objects identified in the Las Campanas Distant Cluster Survey, half with estimated redshift and half with . They were confirmed by identifying red sequences in moderately deep two colour data from VLT/FORS2. For confirmed candidates we have assembled deep three-band optical photometry using VLT/FORS2, deep near-infrared photometry in one or two bands using NTT/SOFI, deep optical spectroscopy using VLT/FORS2, wide field imaging in two or three bands using the ESO Wide Field Imager, and HST/ACS mosaic images for 10 of the most distant clusters. This first paper presents our sample and the VLT photometry we have obtained. We present images, colour–magnitude diagrams and richness estimates for our clusters, as well as giving redshifts and positions for the brightest cluster members. Subsequent papers will present our infrared photometry, spectroscopy, HST and wide-field imaging, as well as a wealth of further analysis and science results. Our reduced data become publicly available as these papers are accepted.