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arXiv · 0811.2239

CARS: the CFHTLS-Archive-Research Survey; I. Five-band multi-colour data from 37 sq. deg. CFHTLS-Wide observations

T. Erben·H. Hildebrandt·M. Lerchster·P. Hudelot·J. Benjamin·L. van Waerbeke·T. Schrabback·F. Brimioulle·O. Cordes·J. P. Dietrich·K. Holhjem·M. Schirmer·P. Schneider
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Abstract

We present the CFHTLS-Archive-Research Survey (CARS). It is a virtual multi-colour survey based on public archive images from the CFHT-Legacy-Survey. Our main scientific interests in CARS are optical searches for galaxy clusters from low to high redshift and their subsequent study with photometric and weak-gravitational lensing techniques. As a first step of the project we present multi-colour catalogues from 37 sq. degrees of the CFHTLS-Wide component. Our aims are to create astrometrically and photometrically well calibrated co-added images. Second goal are five-band (u*, g', r', i', z') multi-band catalogues with an emphasis on reliable estimates for object colours. These are subsequently used for photometric redshift estimates. The article explains in detail data processing, multi-colour catalogue creation and photometric redshift estimation. Furthermore we apply a novel technique, based on studies of the angular galaxy cross-correlation function, to quantify the reliability of photo-z's. The accuracy of our high-confidence photo-z sample (10-15 galaxies per sq. arcmin) is estimated to $σ_{Δ_z/(1+z)}\approx 0.04-0.05$ up to i'<24 with typically only 1-3% outliers. Interested users can obtain access to our data by request to the authors.

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T. Erben, H. Hildebrandt, M. Lerchster, P. Hudelot, J. Benjamin, L. van Waerbeke, T. Schrabback, F. Brimioulle, O. Cordes, J. P. Dietrich, K. Holhjem, M. Schirmer, P. Schneider. 2008-11-13. CARS: the CFHTLS-Archive-Research Survey; I. Five-band multi-colour data from 37 sq. deg. CFHTLS-Wide observations. https://doi.org/10.1051/0004-6361:200810426

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