Polar rings dynamics in the triaxial dark matter halo
  Spectroscopic observations at the Russian 6-m telescope are used to study the
two polar ring galaxies (PRGs) from the catalogue by Moiseev et al.: SPRC-7 and
SPRC-260. We have analyzed the kinematics of the stellar component of the
central galaxies as well as the ionized gas kinematics in the external ring
structures. The disc-halo decomposition of rotation curves in two perpendicular
directions are considered. The observed 2D velocity fields are compared with
the model predictions for different dark halo shapes. Based on these data, we
constrain that for potential of DM halo semiaxis ratios is $s=0.8$, $q=1$ for
SPRC-7 and $s=0.95$, $q=1.1$ for SPRC-260. Using 3D hydrodynamic simulations we
also study the dynamics and evolution of the polar component in the potential
of the galactic disc and dark halo for these two galaxies. We show that the
polar component is dynamically quasi-stable on the scale of $\sim10$ dynamical
times (about a few Gyr). This is demonstrate the possibility for the growth of
a spiral structure, which then steadily transforms to a lopsided gaseous system
in the polar pane.
