EDisCS -- the ESO Distant Cluster Survey -- Sample Definition and Optical Photometry

TL;DR

The EDisCS survey provides a comprehensive multi-wavelength dataset of 20 distant galaxy clusters at redshifts 0.4 to 1.0, including optical, near-infrared, and HST imaging, enabling detailed studies of cluster properties and evolution.

Contribution

This paper introduces the EDisCS sample, detailing the selection, confirmation, and multi-band photometry of distant galaxy clusters, and makes the data publicly available for further research.

Findings

Confirmed 20 distant galaxy clusters using red sequences.

Provided deep optical and near-infrared photometry for the sample.

Published initial images, color-magnitude diagrams, and cluster properties.

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 z_est~0.5 and half with z_est~0.8. 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.