1999MNRAS.308L..11C

We present the results of colour selection of candidate high-redshift galaxies in Hubble Deep Field South (HDF-S) using the Lyman dropout scheme. The HDF-S data we discuss were taken in a number of different filters extending from the near-UV (F300W) to the infrared (F222M) in two different fields. This allows us to select candidates with redshifts from z∼3 to z∼12. We find 15 candidate z∼3 objects (F300W dropouts), one candidate z∼4 object (F450W dropout) and 16 candidate z∼5 objects (F606W dropouts) in the ∼4.7-arcmin² WFPC-2 field, and four candidate z∼6 objects (optical dropouts) and one candidate z∼8 object (F110W dropout) in the 0.84-arcmin² NICMOS-3 field. No F160W dropouts are found (z∼12). We compare our selection technique with existing data for Hubble Deep Field North (HDF-N) and discuss alternative interpretations of the objects. We conclude that there are a number of lower redshift interlopers in the selections, including one previously identified object, and reject those objects most likely to be foreground contaminants. Even after this we conclude that the F606W dropout list is likely to still contain substantial foreground contamination. The lack of candidate very-high-redshift UV-luminous galaxies supports earlier conclusions by Lanzetta et al. We discuss the morphologies and luminosity functions of the high-redshift objects, and their cosmological implications.