  We have used high-resolution, HST WFC3/IR, near-infrared imaging to conduct a
detailed bulge-disk decomposition of the morphologies of ~200 of the most
massive (M_star > 10^11 M_solar) galaxies at 1<z<3 in the CANDELS-UDS field. We
find that, while such massive galaxies at low redshift are generally
bulge-dominated, at redshifts 1<z<2 they are predominantly mixed bulge+disk
systems, and by z>2 they are mostly disk-dominated. Interestingly, we find that
while most of the quiescent galaxies are bulge-dominated, a significant
fraction (25-40%) of the most quiescent galaxies, have disk-dominated
morphologies. Thus, our results suggest that the physical mechanisms which
quench star-formation activity are not simply connected to those responsible
for the morphological transformation of massive galaxies.
