The VIMOS VLT Deep Survey: ? The K-band follow-up in the 0226 04 field

We present a new K_s-band survey that represents a significant extension to the previous wide-field K_s-band imaging survey within the 0226-04 field of the VIMOS-VLT deep survey (VVDS). The new data add ~458 arcmin2 to the previous imaging program, thus allowing us to cover a total contiguous area of ~600 arcmin2 within this field. Sources were identified both directly on the final K-band mosaic image and on the corresponding, deep χ^2-g'r'i' image from the CFHT Legacy Survey in order to reduce contamination, while ensuring compilation of a truly K-selected catalogue down to the completeness limit of the K_s-band. The newly determined K_s-band magnitudes are used in combination with the ancillary multiwavelength data for determining accurate photometric redshifts. The final catalogue totals ~52 000 sources, out of which ~4400 have a spectroscopic redshift from the VVDS first epoch survey. The catalogue is 90% complete down to KVega = 20.5 mag. We present K_s-band galaxy counts and angular correlation function measurements down to this magnitude limit. Our results are in good agreement with previously published work. We show that using K magnitudes to determine photometric redshifts significantly lowers the incidence of catastrophic errors. The data presented in this paper are publicly available through the CENCOS database. Based on observations collected at the European Southern Observatory New Technology Telescope, La Silla, Chile, programme 075.A-0752(A), on data obtained with the European Southern Observatory Very Large Telescope, Paranal, Chile, programme 070.A-9007(A), and on observations obtained with MegaPrime/MegaCam, a joint project of CFHT and CEA/DAPNIA, at the Canada-France-Hawaii Telescope (CFHT), which is operated by the National Research Council (NRC) of Canada, the Institut National des Science de l'Univers of the Centre National de la Recherche Scientifique (CNRS) of France, and the University of Hawaii. This work is based in part on data products produced at TERAPIX and the Canadian Astronomy Data Centre as part of the Canada-France-Hawaii Telescope Legacy Survey, a collaborative project of NRC and CNRS.