The Great Observatories Origins Deep Survey - VLT/FORS2 Spectroscopy in the GOODS-South Field

Abstract

We present the first results of the ESO/GOODS program of spectroscopy of faint galaxies in the Chandra Deep Field South (CDF-S). 399 spectra of 303 unique targets have been obtained in service mode with the FORS2 spectrograph at the ESO/VLT, providing 234 redshift determinations (the median of the redshift distribution is at 1.04). The typical redshift uncertainty is estimated to be sig(z) ~ 0.001. Galaxies have been color selected in a way that the resulting redshift distribution typically spans from z=0.5 to 2. The reduced spectra and the derived redshifts are released to the community through the ESO web page http://www.eso.org/science/goods/ Large scale structure is clearly detected at z ~ 0.67, 0.73, 1.10 and 1.61. Three Lyman-break galaxies have also been included as targets and are confirmed to have redshifts z=4.800, 4.882 and 5.828. In a few cases, we observe clear [OII]3727 rotation curves, even at the relatively low resolution (R = 860) of the present observations. Assuming that the observed velocity structure is due to dynamically-relaxed rotation, this is an indication of large galactic masses (few times 10^(11) solar masses) at z ~ 1.