The SINS survey: modeling the dynamics of z~2 galaxies and the high-z
  Tully-Fisher relation
  We present the modeling of SINFONI integral field dynamics of 18 star forming
galaxies at z ~ 2 from Halpha line emission. The galaxies are selected from the
larger sample of the SINS survey, based on the prominence of ordered rotational
motions with respect to more complex merger induced dynamics. The quality of
the data allows us to carefully select systems with kinematics dominated by
rotation, and to model the gas dynamics across the whole galaxy using suitable
exponential disk models. We obtain a good correlation between the dynamical
mass and the stellar mass, finding that large gas fractions Mgas~M*) are
required to explain the difference between the two quantities. We use the
derived stellar mass and maximum rotational velocity Vmax from the modeling to
construct for the first time the stellar mass Tully-Fisher relation at z ~ 2.2.
The relation obtained shows a slope similar to what is observed at lower
redshift, but we detect an evolution of the zero point. We find that at z ~ 2.2
there is an offset in log(M*) for a given rotational velocity of 0.41+-0.11
with respect to the local Universe. This result is consistent with the
predictions of the latest N-body/hydrodynamical simulations of disk formation
and evolution, which invoke gas accretion onto the forming disk in filaments
and cooling flows. This scenario is in agreement with other dynamical evidence
from SINS, where gas accretion from the halo is required to reproduce the
observed properties of a large fraction of the z ~ 2 galaxies.
