Deep U Band and R Imaging of Goods-South: Observations, Data Reduction and First Results

Abstract

We present deep imaging in the U band covering an area of 630 arcmin² centered on the southern field of the Great Observatories Origins Deep Survey (GOODS). The data were obtained with the VIMOS instrument at the European Southern Observatory (ESO) Very Large Telescope. The final images reach a magnitude limit U _lim ≈ 29.8 (AB, 1σ, in a 1'' radius aperture), and have good image quality, with full width at half-maximum ≈0farcs8. They are significantly deeper than previous U-band images available for the GOODS fields, and better match the sensitivity of other multiwavelength GOODS photometry. The deeper U-band data yield significantly improved photometric redshifts, especially in key redshift ranges such as 2 < z < 4, and deeper color-selected galaxy samples, e.g., Lyman break galaxies at z ≈ 3. We also present the co-addition of archival ESO VIMOS R-band data, with R _lim ≈ 29 (AB, 1σ, 1'' radius aperture), and image quality ≈0farcs75. We discuss the strategies for the observations and data reduction, and present the first results from the analysis of the co-added images.

Based on observations taken with European Southern Observatory Very Large Telescope, Paranal, Chile, LP 168.A-0485(C).

Based on observations made with the European Southern Observatory (ESO) telescopes obtained from the ESO/ST-ECF Science Archive Facility: 071.A-3036, 072.A-0586, 074.A-0280, 074.A-0303, 074.A-0509, 075.A-0481, 078.A-0485, 078.B-0425, 080.A-0566, 080.A-0411, 167.D-0492, 171.A-3045, 080. Also based on observations obtained with the NASA/ESO Hubble Space Telescope obtained at the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc. (AURA) under NASA contract NAS 5-26555.