Astron. Astrophys. 345, 448-460 (1999)

1. Introduction

The present paper is part of a series presenting the data accumulated by the public ESO Imaging Survey (EIS) being carried out in preparation for the first year of regular operation of the VLT. As described in previous papers (Renzini & da Costa 1997, Nonino et al. 1999, hereafter paper I) the main science goal of EIS is the search for rare objects such as clusters of galaxies, spanning a broad redshift range, quasars at intermediate and high redshifts, high-redshift galaxies and stars with special characteristics (e.g., white dwarfs, very low mass stars, brown dwarfs). These goals have guided the adopted survey strategy which, for EIS-wide, envisioned observations in V and I to search for clusters and in four passbands () over square degrees in a region near the South Galactic Pole (EIS-wide patch B). The observations in and I have already been completed, while observations in the U-band are expected to be carried out in the fall of 1999.

One of the main motivations for the multicolor survey has been the identification of a large number of close line-of-sight, intermediate redshift QSOs to study the three-dimensional distribution of absorbers, using medium and high-resolution spectrographs (e.g., UVES) at the VLT. For this reason, a region near the SGP, where several QSOs are known from previous studies, has been selected. However, the data are also useful for galactic studies and for the identification of rare stellar populations, with the survey having a unique combination of depth and area coverage. The additional V-band images, which altogether overlap the I images over 70% of the surveyed area in patches A and B (15% of the whole EIS-wide), are also useful in the search of galaxy clusters (e.g., Olsen et al. 1999, paper V). Finally, it is important to emphasize that the present data offer an excellent opportunity to assess the complexity of efficiently handling large volumes of multicolor data and extracting useful target lists. This is a key element for the exploration of the full range of science offered by the multicolor surveys envisioned for the new wide-field camera (WFI@2.2m) at the ESO/MPIA 2.2m telescope at La Silla.

In Sect. 2, the observations are described and the characteristics of the multicolor data are presented. This section also presents the extracted object catalogs and discusses their completeness and reliability. In Sect. 3 the catalogs are evaluated by comparison with models and other data. Concluding remarks are presented in Sect. 4.

© European Southern Observatory (ESO) 1999

Online publication: April 19, 1999
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