Deep U band and R imaging of GOODS-South: Observations,data reduction and first results

TL;DR

This paper reports deep U and R band imaging of the GOODS-South field using VIMOS at the VLT, achieving unprecedented depth and quality, which improves photometric redshifts and galaxy selection for high-redshift studies.

Contribution

It provides the deepest U and R band images for GOODS-South to date, enhancing multi-wavelength data and enabling more accurate photometric redshifts and galaxy samples at high redshift.

Findings

U-band images reach magnitude limit ~29.8, significantly deeper than previous data.

Improved photometric redshifts, especially for 2<z<4.

Enhanced selection of high-redshift galaxies like Lyman-break galaxies.

Abstract

We present deep imaging in the {\em U} band covering an area of 630 arcmin$^{2}$ centered on the southern field of the Great Observatories Origins Deep Survey (GOODS). The data were obtained with the VIMOS instrument at the ESO Very Large Telescope. The final images reach a magnitude limit $U_{lim} \approx 29.8$ (AB, 1$\sigma$, in a 1\arcsec radius aperture), and have good image quality, with full width at half maximum $\approx 0.8\arcsec$. They are significantly deeper than previous U--band images available for the GOODS fields, and better match the sensitivity of other multi--wavelength 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 $z\approx 3$. We also present the coaddition of archival ESO VIMOS R band data, with $R_{lim} \approx 29$ (AB, 1$\sigma$, 1\arcsec radius aperture), and image quality $\approx 0.75 \arcsec$. We discuss the strategies for the observations and data reduction, and present the first results from the analysis of the coadded images.