VLT and HST observations of a candidate high redshift elliptical galaxy inthe Hubble Deep Field South

The combined use of the ESO Very Large Telescope (VLT) UTI Science Verifica tion (SV) images and of the Hubble Space Telescope (HST) Hubble Deep Field South observations allows us to strengthen the identification as a candidat e elliptical galaxy of the Extremely Red Object HDFS 223251-603910 previous ly identified by us on the basis of NICMOS and Cerro Tololo Interamerican O bservatory imaging. The photometry presented here includes VLT data in U, B , V, R, I, a STIS unfiltered image, MCMOS J, H, and K band data, thus combi ning the 16.5 hours of VLT SV exposures with 101 hours of HST observing. Th e object is detected in all images except the VLT U band and is one of the reddest known with B-K= 9.7 +/- 0.5. We consider a wide range of models wit h different ages, metallicities, star formation histories and dust content, and conclude that the observed spectral energy distribution agrees best wi th that of an old elliptical galaxy at redshift just below 2. Alternative p ossibilities are discussed in light of their likelihood and of the perspect ive of spectroscopic confirmation.