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