CANDELS: The correlation between galaxy morphology and star formation
  activity at z~2
  We discuss the state of the assembly of the Hubble Sequence in the mix of
bright galaxies at redshift 1.4< z \le 2.5 with a large sample of 1,671
galaxies down to H_{AB}~26, selected from the HST/ACS and WFC3 images of the
GOODS--South field obtained as part of the GOODS and CANDELS observations. We
investigate the relationship between the star formation properties and
morphology using various parametric diagnostics, such as the Sersic light
profile, Gini (G), M_{20}, Concentration (C), Asymmetry (A) and multiplicity
parameters. Our sample clearly separates into massive, red and passive galaxies
versus less massive, blue and star forming ones, and this dichotomy correlates
very well with the galaxies' morphological properties. Star--forming galaxies
show a broad variety of morphological features, including clumpy structures and
bulges mixed with faint low surface brightness features, generally
characterized by disky-type light profiles. Passively evolving galaxies, on the
other hand, very often have compact light distribution and morphology typical
of today's spheroidal systems. We also find that artificially redshifted local
galaxies have a similar distribution with z~2galaxies in a G-M_{20} plane.
Visual inspection between the rest-frame optical and UV images show that there
is a generally weak morphological k-correction for galaxies at z~2, but the
comparison with non-parametric measures show that galaxies in the rest-frame UV
are somewhat clumpier than rest-frame optical. Similar general trends are
observed in the local universe among massive galaxies, suggesting that the
backbone of the Hubble sequence was already in place at z~2.
