The stellar kinematics in the solar neighborhood from LAMOST data
  We use about 200,000 FGK type main-sequence stars from the LAMOST DR1 data to
map the local stellar kinematics. With the velocity de-projection technique, we
are able to derive the averaged 3 dimensional velocity and velocity ellipsoids
using only the line-of-sight velocity for the stars with various effective
temperatures within $100 < |z| < 500$ pc. Using the mean velocities of the cool
stars, we derive the solar motion of ($U_{\!\odot}$, $V_{\!\odot}$,
$W_{\!\odot}$)=(9.58$\pm2.39$, 10.52$\pm1.96$, 7.01$\pm1.67$)$km\,s^{-1}$ with
respect to the local standard of rest. Moreover, we find that the stars with
${T}_{\rm eff}>6000$K show a net asymmetric motion of $\sim3 km\,s^{-1}$ in
$\langle W\rangle$ compared to the stars with ${T}_{\rm eff}<6000$K. And their
azimuthal velocity increases when $|z|$ increases. This peculiar motion in the
warmer stars is likely because they are young and not completely relaxed,
although other reasons, such as the resonance induced by the central rotating
bar or the spiral structures, and the perturbation of the merging dwarf
galaxies, can not be ruled out. The derived velocity dispersions and cross
terms for the data are approximately consistent with previous studies. We also
find that the vertical gradients of $\sigma_{U}$ and $\sigma_V$ are larger than
that of $\sigma_W$ . And the vertical gradient of $\sigma_U$ shows clear
correlation with ${T}_{\rm eff}$, while the other two do not. Finally, our
sample shows vertex deviation of about 11$^\circ$, at $300 < |z| < 500$pc, but
roughly zero at $100 < |z| < 300$pc.
