The WIRCam Ultra Deep Survey (WUDS)

I. Survey overview and UV luminosity functions at z  ∼  5 and z  ∼  6^⋆

¹ Institut de Recherche en Astrophysique et Planétologie (IRAP), Université de Toulouse, CNRS, UPS, CNES, 14 Av. Edouard Belin, 31400 Toulouse, France
e-mail: rpello@irap.omp.eu
² Institut d’Astrophysique de Paris, UMR7095 CNRS, Université Pierre & Marie Curie, 98 bis Bld. Arago, 75014 Paris, France
³ Department of Physics and Astronomy, University College London, Gower Street, London, WC1E 6BT UK
⁴ Instituto de Astrofísica de Canarias, C/ Via Lactea s/n, 38205 La Laguna, Tenerife, Spain
⁵ Departamento de Astrofísica, Universidad de La Laguna, Avda. Astrofísico Fco. Sànchez, 38206 La Laguna, Tenerife, Spain
⁶ Departamento de Astrofísica y CC de la Atmósfera, Universidad Complutense de Madrid, Av Complutense s/n, 28040 Madrid, Spain
⁷ Department of Astronomy, University of Florida, 211 Bryant Space Science Center, Gainsville, FL, 32611-2055 USA
⁸ Université Lyon 1, ENS de Lyon, CNRS, Centre de Recherche Astrophysique de Lyon (CRAL) UMR5574, 69230 Saint-Genis-Laval, France
⁹ Geneva Observatory, Chemin des Maillettes 51, 1290 Versoix, Switzerland
¹⁰ Laboratoire d’Astrophysique de Marseille, CNRS – Université Aix-Marseille, 38 Rue Frédéric Joliot-Curie, 13388 Marseille Cedex 13, France
¹¹ Stockholm University, Department of Astronomy and Oskar Klein Centre for Cosmoparticle Physics, AlbaNova University Centre, 10691 Stockholm, Sweden

Received: 11 October 2017
Accepted: 3 September 2018

Abstract

The aim of this paper is to introduce the WIRCam Ultra Deep Survey (WUDS), a near-IR photometric survey carried out at the CFH Telescope in the field of the CFHTLS-D3 field (Groth Strip). WUDS includes four near-IR bands (Y, J, H and K_s) over a field of view of ∼400 arcmin². The typical depth of WUDS data reaches between ∼26.8 in Y and J, and ∼26 in H and K_s (AB, 3σ in 1.3″ aperture), whereas the corresponding depth of the CFHTLS-D3 images in this region ranges between 28.6 and 29 in ugr, 28.2 in i and 27.1 in z (same S/N and aperture). The area and depth of this survey were specifically tailored to set strong constraints on the cosmic star formation rate and the luminosity function brighter or around L^⋆ in the z ∼ 6 − 10 redshift domain, although these data are also useful for a variety of extragalactic projects. This first paper is intended to present the properties of the public WUDS survey in details: catalog building, completeness and depth, number counts, photometric redshifts, and global properties of the galaxy population. We have also concentrated on the selection and characterization of galaxy samples at z ∼ [4.5 − 7] in this field. For these purposes, we include an adjacent shallower area of ∼1260 arcmin² in this region, extracted from the WIRCam Deep Survey (WIRDS), and observed in J, H and K_s bands. UV luminosity functions were derived at z ∼ 5 and z ∼ 6 taking advantage from the fact that WUDS covers a particularly interesting regime at intermediate luminosities, which allows a combined determination of M^⋆ and Φ^⋆ with increased accuracy. Our results on the luminosity function are consistent with a small evolution of both M^⋆ and Φ^⋆ between z = 5 and z = 6, irrespective of the method used to derive them, either photometric redshifts applied to blindly-selected dropout samples or the classical Lyman Break Galaxy color-preselected samples. Our results lend support to higher Φ^⋆ determinations at z = 6 than usually reported. The selection and combined analysis of different galaxy samples at z ≥ 7 will be presented in a forthcoming paper, as well as the evolution of the UV luminosity function between z ∼ 4.5 and 9. WUDS is intended to provide a robust database in the near-IR for the selection of targets for detailed spectroscopic studies, in particular for the EMIR/GTC GOYA Survey.