Evidence for Morphology and Luminosity Transformation of Galaxies at
  High Redshifts
  We study the galaxy morphology-luminosity-environmental relation and its
redshift evolution using a spectroscopic sample of galaxies in the Great
Observatories Origins Deep Survey (GOODS). In the redshift range of $0.4\leq
z\leq1.0$ we detect conformity in morphology between neighboring galaxies. The
realm of conformity is confined within the virialized region associated with
each galaxy plus dark matter halo system. When a galaxy is located within the
virial radius of its nearest neighbor galaxy, its morphology strongly depends
on the neighbor's distance and morphology: the probability for a galaxy to be
an early type ($f_E$) strongly increases as it approaches an early-type
neighbor, but tends to decrease as it approaches a late-type neighbor. We find
that $f_E$ evolves much faster in high density regions than in low density
regions, and that the morphology-density relation becomes significantly weaker
at $z\approx 1$. This may be because the rate of galaxy-galaxy interactions is
higher in high density regions, and a series of interactions and mergers over
the course of galaxy life eventually transform late types into early types. We
find more isolated galaxies are more luminous, which supports luminosity
transformation through mergers at these redshifts. Our results are consistent
with those from nearby galaxies, and demonstrate that galaxy-galaxy
interactions have been strongly affecting the galaxy evolution over a long
period of time.
