Constraints on the Early Formation of Field Elliptical Galaxies

We present the results of an HK′ wide-field survey encompassing the Hubble Deep Field and its flanking fields. Our wide-field survey provides uniform coverage of a 61.8 arcmin2 area to a depth equivalent to K = 20.1 at 5 σ. We have also imaged the Hubble Deep Field in HK′, providing uniform coverage of a 7.8 arcmin2 area to a depth equivalent to K = 21.2 at 5 σ. Using these data in combination with new deep University of Hawaii 8K V and I imaging obtained on the Canada-France-Hawaii Telescope, we find only a small population of objects with colors redder than an equivalent I-K = 4, the color expected for an evolved elliptical galaxy at z > 1. We infer that only a fraction of the local field elliptical galaxy population with MK < -23.4 could have formed in single bursts at high redshift.