C. Benoist

ESO Imaging Survey. VII. Distant cluster candidates over 12 square degrees

In this paper the list of candidate clusters identified from the I -band images of the ESO Imaging Survey (EIS) is completed using the data obtained over a total area of about 12 square degrees (EIS Patchesxa0C and D). 248 new cluster candidates are presented. Together with the data reported earlier the total I -band coverage of EIS is 17 square degrees, which has yielded a sample of 302 cluster candidates with estimated redshift in the range and a median redshift of . This is the largest optically-selected sample currently available in the Southern Hemisphere. It is also well distributed in the sky thus providing targets for a variety of VLT programs nearly year round.

ESO imaging survey: infrared deep public survey

This paper presents new J and Ks data obtained from observations conducted at the ESO 3.5m New Technology Telescope using the SOFI camera. These data were taken as part of the ESO Imaging Survey Deep Public Survey (DPS) and significantly extend the earlier optical/infrared EIS-DEEP survey presented in a previous paper. The DPS-IR survey comprises two observing strategies: shallow Ks observations providing nearly full coverage of pointings with complementary multi-band optical data and deeper J and Ks observations of the central parts of these fields. The DPS-IR survey provides a coverage of roughly 2.1 square degrees in Ks with 0.63 square degrees to fainter magnitudes and also covered in J, over three independent regions of the sky. The goal of the present paper is to describe the observations, the data reduction procedures, and to present the final survey products. The astrometric solution with an estimated accuracy of <0.15 is based on the USNO catalog. The final stacked images presented here number 89 and 272, in J and Ks, respectively, the latter reflecting the larger surveyed area. The J and Ks images were taken with a median seeing of 0.77 and 0.8. The images reach a median 5sigma limiting magnitude of J_AB~23.06 in an aperture of 2, while the corresponding limiting magnitude in Ks_AB is ~21.41 and ~22.16 mag for the shallow and deep strategies. Overall, the observed limiting magnitudes are consistent with those originally proposed. The quality of the data has been assessed by comparing the measured magnitude of sources at the bright end directly with those reported by the 2MASS survey and at the faint end by comparing the counts of galaxies and stars with those of other surveys to comparable depth and to model predictions. The final science-grade catalogs and images are available at CDS.

Properties of Very Luminous Galaxies

Recent analysis of the data from the Southern Sky Redshift Survey extension (SSRS2) based on cell counts and the two-point correlation function has shown that very luminous galaxies are much more strongly clustered than fainter galaxies. In fact, the amplitude of the correlation function of very luminous galaxies (L > L*) asymptotically approaches that of R ≥ 0 clusters. In this paper we investigate the properties of the most luminous galaxies, with blue absolute magnitudes MB ≤ -21. We find that (1) the population mix is comparable to that in other ranges of absolute magnitude; (2) only a small fraction are located in bona fide clusters; (3) the bright galaxy–cluster cross-correlation function is significantly higher on large scales than that measured for fainter galaxies; (4) the correlation length of galaxies brighter than MB ~ -20.0, expressed as a function of the mean interparticle distance, appears to follow the universal dimensionless correlation function found for clusters and radio galaxies; (5) a large fraction of the bright galaxies are in interacting pairs, while others show evidence for tidal distortions and some appear to be surrounded by faint satellite galaxies. We conclude that very luminous optical galaxies differ from the normal population of galaxies in both clustering and other respects. We speculate that this population is a highly biased tracer of mass, being associated with dark halos with masses more comparable to clusters than to typical loose groups.

ESO imaging survey: optical follow-up of 12 selected XMM-Newton fields ,

This paper presents the data recently released for the XMM-Newton/WFI survey carried out as part of the ESO Imaging Survey (EIS) project. The aim of this survey is to provide optical imaging follow-up data in BVRI for identification of serendipitously detected X-ray sources in selected XMM-Newton fields. In this paper, fully calibrated individual and stacked images of 12 fields as well as science-grade catalogs for the 8 fields located at high-galactic latitude are presented. These products were created, calibrated and released using the infrastructure provided by the EIS Data Reduction system and its associated EIS/MVM image processing engine, both of which are briefly described here. The data covers an area of ∼3 square degrees for each of the four passbands. The median seeing as measured in the final stacked images is 0. �� 94, ranging from 0. �� 60 and 1. �� 51. The median limiting magnitudes (AB system, 2 �� aperture, 5σ detection limit) are 25.20, 24.92, 24.66, and 24.39 mag for B-, V-, R-, and I-band, respectively. When only the 8 high-galactic latitude fields are included these become 25.33, 25.05, 25.36, and 24.58 mag, in good agreement with the planned depth of the survey. Visual inspection of images and catalogs, comparison of statistics derived from the present data with those obtained by other authors and model predictions, as well as direct comparison of the results obtained from independent reductions of the same data, demonstrate the science-grade quality of the automatically produced final images and catalogs. These survey products, together with their logs, are available to the community for science exploitation in conjunction with their X-ray counterparts. Preliminary results from the X-ray/optical cross-correlation analysis show that about 61% of the detected X-ray point sources in deep XMM-Newton exposures have at least one optical counterpart within 2 �� radius down to R � 25 mag, 50% of which are so faint as to require VLT observations thereby meeting one of the top requirements of the survey, namely to produce large samples for spectroscopic follow-up with the VLT, whereas only 15% of the objects have counterparts down to the DSS limiting magnitude.

ESO imaging survey: infrared observations of CDF-S and HDF-S

This paper presents infrared data obtained from observations carried out at the ESO 3.5 m New Technology Telescope (NTT) of the Hubble Deep Field South (HDF-S) and the Chandra Deep Field South (CDF-S). These data were taken as part of the ESO Imaging Survey (EIS) program, a public survey conducted by ESO to promote follow-up observations with the VLT. In the HDF-S field the infrared observations cover an area of ∼53 square arcmin, encompassing the HST WFPC2 and STIS fields, in the JHK s passbands. The seeing measured in the final stacked images ranges from 0.79 to 1.22 and the median limiting magnitudes (AB system, 2 aperture, 5σ detection limit) are J AB ∼ 23.0, H AB ∼ 22.8 and K AB ∼ 23.0 mag. Less complete data are also avai]able in JK s for the adjacent HST NICMOS field. For CDF-S, the infrared observations cover a total area of ∼100 square arcmin, reaching median limiting magnitudes (as defined above) of J AB ∼ 23.6 and K AB ∼ 22.7 mag. For one CDF-S field H band data are also available. This paper describes the observations and presents the results of new reductions carried out entirely through the un-supervised, high-throughput EIS Data Reduction System and its associated EIS/MVM C++-based image processing library developed, over the past 5 years, by the EIS project and now publicly available. The paper also presents source catalogs extracted from the final co-added images which are used to evaluate the scientific quality of the survey products, and hence the performance of the software. This is done comparing the results obtained in the present work with those obtained by other authors from independent data and/or reductions carried out with different software packages and techniques. The final science-grade catalogs together with the astrometrically and photometrically calibrated co-added images are available at CDS.