Determination of the Local Standard of Rest using the LSS-GAC DR1
  We re-estimate the peculiar velocity of the Sun with respect to the local
standard of rest using a sample of local stars within 600 pc of the Sun,
selected from the LAMOST Spectroscopic Survey of the Galactic Anti-centre
(LSS-GAC). The sample consists of 94332 FGK main-sequence stars with
well-determined radial velocities and atmospheric parameters. To derive the
LSR, two independent analyses are applied to the data. Firstly, we determine
the solar motion by comparing the observed velocity distribution to that
generated with the analytic formulism of Schonrich & Binney that has been
demonstrated to show excellent agreement with rigorous torus-based dynamics
modelling by Binney & McMillan. Secondly, we propose that cold populations of
thin disc stars, selected by applying an orbital eccentricity cut, can be
directly used to determine the LSR without the need of asymmetric drift
corrections. Both approaches yield consistent results of solar motion in the
direction of Galactic rotation, V_sun, that are much higher than the standard
value adopted hitherto, derived from Stromgren's equation. The newly deduced
values of V_sun are 1-2 km/s smaller than the more recent estimates derived
from the Geneva-Copenhagen Survey sample of stars in the solar neighbourhood
(within 100 pc). We attribute the small difference to the presence of several
well-known moving groups in the GCS sample that, fortunately, hardly affect the
LSS-GAC sample. The newly derived radial and vertical components of the solar
motion agree well with the previous studies. In addition, for all components of
the solar motion, the values yielded by stars of different spectral types in
the LSS-GAC sample are consistent with each other, suggesting that the local
disk is well relaxed and that the LSR reported in the current work is robust.
Our final recommended LSR is, (U,V,W)_sun = (7.01+/-0.20, 10.13+/-0.12,
4.95+/-0.09) km/s.
