  Photometric redshifts have been determined for the galaxies in the Hubble
Deep Field. The resulting redshift distribution shows two peaks: one at z~0.6
and one at z~2.2. Luminosity functions derived from the redshifts show strong
luminosity evolution as a function of redshift. This evolution is consistent
with the Babul & Rees (1992) scenario wherein massive galaxies form stars at
high redshift while star formation in dwarf galaxies is delayed until after
z=1.
