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G. Rudnick (MPIA/Steward Observatory), H.-W. Rix (MPIA), M. Franx (Leiden Observatory)
Recent searches for high redshift galaxies select them on the basis of strong breaks in their rest-frame UV spectral energy distribution (SED). The success of these searches has made possible, for the first time, the measurement of the instantaneous star-formation rate (SFR) of the universe. However the rest-frame V-band is shifted into the near infrared by z=0.5, and so these same optical surveys are not sensitive to the light from the stars which dominate the stellar \textit{mass} budget. To more directly measure the stellar mass build-up of the universe, we have obtained deep JHKs images (~ 32 hours per passband) of the Hubble Deep Field South (HDF-S) as part of the the Faint InfraRed Extra-galactic Survey (FIRES) at the VLT. We couple this with the deep, optical HST WFPC2 data from this same field. We select galaxies in the K-band and hence, out to z=3, by their rest-frame optical light. Using the seven-band information from the HST + VLT data, we obtain photometric redshifts of all galaxies in a magnitude limited, K-band selected catalog. Once the redshift is measured, we can use the observed colors to constrain the intrinsic SED. We measure the rest-frame V-band luminosity of all of the galaxies in our sample and find a large number of bright galaxies with LV > LV* and 1< z < 3. Some of these bright galaxies have strong Balmer Breaks or 4000Å breaks indicating the presence of evolved stellar populations. A preliminary analysis shows that these evolved, luminous galaxies contribute comparably to the stellar mass budget at these redshifts as the Lyman Break Galaxies. This work is supported by the Max-Plank-Institut für Astronomie.
The author(s) of this abstract have provided an email address for comments about the abstract: grudnick@mpia-hd.mpg.de