The Fraction of High Redshift Galaxies in Deep Infrared Selected Field Galaxy Samples

Recent results on the incidence of red galaxies in a > 100 square arcminute field galaxy survey to K = 20 and a K = 22 survey of the Hubble Deep Field are presented. We argue that a simple photometric redshift indicator, based on J−K color and supported by spectroscopic results obtained with Keck, gives a reliable lower limit of ∼ 25% for the fraction of z > 1 galaxies in the 100 square arcminute survey. This fraction is substantially higher than found in previous smaller samples, and is at least as consistent with predictions for pure luminosity evolution as with those for hierarchical models. The same technique yields a very low fraction for the HDF, which appears to be unusually underabundant in red galaxies.