  We present the first comparison of the dynamical properties of different
samples of z~1.4-3.4 star forming galaxies from spatially resolved imaging
spectroscopy from SINFONI/VLT integral field spectroscopy and IRAM CO
millimeter interferometry. Our samples include 16 rest-frame UV-selected, 16
rest-frame optically-selected and 13 submillimeter galaxies (SMGs). We find
that restframe UV- and optically bright (K<20) z~2 star forming galaxies are
dynamically similar, and follow the same velocity-size relation as disk
galaxies at z~0. In the theoretical framework of rotating disks forming from
dissipative collapse in dark matter halos, the two samples require a spin
parameter ranging from 0.06 to 0.2. In contrast bright SMGs have larger
velocity widths and are much more compact. Hence, SMGs have lower angular
momenta and higher matter densities than either of the UV- or optically
selected populations. This indicates that dissipative major mergers may
dominate the SMGs population, resulting in early spheroids, and that the
majority of UV/optically bright galaxies have evolved less violently [...].
These early disks may later evolve into spheroids via disk instabilities or
mergers. Because of their small sizes and large densities, SMGs lie at the high
surface density end of a universal (out to z=2.5) "Schmidt-Kennicutt" relation
between gas surface density and star formation rate surface density with a
slope of ~1.7.
