The WIRCam Ultra Deep Survey (WUDS)

R. Pelló (1) , P. Hudelot (2) , N. Laporte , Y. Mellier , H. J. Mccracken (2) , M. Balcells (3) , F. Boone , N. Cardiel , J. Gallego , F. Garzón , R. Guzmán (4) , J. F. Le Borgne (5) , M. Prieto , J. Richard , D. Schaerer , L. Tresse (6) , S. Arnouts (6) , J. G. Cuby (6) , K. Disseau (7) , M. Hayes

1 IRAP - Institut de recherche en astrophysique et planétologie
2 IAP - Institut d'Astrophysique de Paris
3 Department of Chemistry
4 LMD - Laboratoire de Météorologie Dynamique (UMR 8539)
5 AGROCAMPUS OUEST
6 LAM - Laboratoire d'Astrophysique de Marseille
7 GEPI - Galaxies, Etoiles, Physique, Instrumentation

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 Ks) 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 Ks (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 Ks 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.

Mots clés: surveys; galaxies: high-redshift; dark ages; reionization; first stars

Domaines: Astrophysique [astro-ph]

R. Pelló, P. Hudelot, N. Laporte, Y. Mellier, H. J. Mccracken, et al.. The WIRCam Ultra Deep Survey (WUDS): I. Survey overview and UV luminosity functions at z  ∼  5 and z  ∼  6. Astronomy and Astrophysics - A&A, 2018, 620, pp.A51. ⟨10.1051/0004-6361/201732080⟩. ⟨hal-03000018⟩