Morpho-kinematics of z~1 galaxies probe the hierarchical scenario
  We have studied a representative sample of intermediate-mass galaxies at z~1,
observed by the kinematic survey KMOS3D. We have re-estimated the kinematical
parameters from the published kinematic maps and analysed photometric data from
HST to measure optical disk inclinations and PAs. We find that only half of the
z~1 galaxies show kinematic properties consistent with rotating disks, using
the same classification scheme than that adopted by the KMOS3D team. Because
merger orbital motions can also brought rotation, we have also analysed galaxy
morphologies from the available HST imagery. Combining these results to those
from kinematics, it leads to a full morpho-kinematic classification. To test
the robustness of the latter for disentangling isolated disks from mergers, we
confronted the results with an analysis of pairs from the open-grism redshift
survey 3D-HST. All galaxies found in pairs are affected by either kinematic
and/or morphological perturbations. Conversely, all galaxies classified as
virialized spirals are found to be isolated. A significant fraction (one
fourth) of rotating disks classified from kinematics by the KMOS3D team are
found in pairs, which further supports the need for a morpho-kinematic
classification. It results that only one third of z~1 galaxies are isolated and
virialized spirals, while 58% of them are likely involved in a merger sequence,
from first approach to disk rebuilding. The later fraction is in good agreement
with the results of semi-empirical {\Lambda}CDM models, supporting a
merger-dominated hierarchical scenario as being the main driver of galaxy
formation at least during the last 8 billion years.
