Multicolor observations of the hubble deep field south

We present a deep multicolor (U, B, V, I, Js, H, Ks) catalog of galaxies in the Hubble Deep Field South, based on observations obtained with the HST W FPC2 in 1998 and VLT-ISAAC in 1999. The photometric procedures were tuned t o derive a catalog optimized for the estimation of photometric redshifts. I n particular we adopted a "conservative" detection threshold, which resulte d in a list of 1611 objects. The behavior of the observed source counts is in general agreement with the previous results of Casertano et al. in the H ubble Deep Field South and Williams et al. in the Hubble Deep Field North, while the corresponding counts in the Hubble Deep Field North provided by L anzetta, Fernandez-Soto, & Yahil are systematically lower by a factor 1.5 b eyond I-AB = 26. After correcting for the incompleteness of the source coun ts, the object surface density I-AB less than or equal to 27.5 at is estima ted to be 220 arcmin(-2), in agreement with the corresponding measure of Vo lonteri et al. and providing an estimate of the extragalactic background li ght in the I band consistent with the work of Madau & Pozzetti. The compari son between the median V-I color in the Hubble Deep Field North and South s hows a significant difference around I-AB similar to 26, possibly due to th e presence of large-scale structure at z similar to 1 in the HDF-N. High-re dshift galaxy candidates (90 U dropouts and 17 B dropouts) were selected by means of color diagrams, down to a magnitude I-AB = 27, with a surface den sity of (21 +/- 1) and (3.9 +/- 0.9) arcmin(-2), respectively. Eleven extre mely red objects [with (I-K)(AB) > 2.7] were selected down to K-AB = 24, pl us three objects whose upper limit to the Ks flux is still compatible with the selection criterion. The corresponding surface density of EROs is (2.5 +/- 0.8) arcmin(-2) [(3.2 +/- 0.9) arcmin(-2) if we include the three Ks up per limits]. They show a remarkably nonuniform spatial distribution and are classified with roughly equal fractions in the categories of elliptical an d starburst galaxies.