The Milky Way's rotation curve out to 100 kpc and its constraint on the
  Galactic mass distribution
  The rotation curve (RC) of the Milky Way out to $\sim$ 100 kpc has been
constructed using $\sim$ 16,000 primary red clump giants (PRCGs) in the outer
disk selected from the LSS-GAC and the SDSS-III/APOGEE survey, combined with
$\sim$ 5700 halo K giants (HKGs) selected from the SDSS/SEGUE survey. To derive
the RC, the PRCG sample of the warm disc population and the HKG sample of halo
stellar population are respectively analyzed using a kinematical model allowing
for the asymmetric drift corrections and re-analyzed using the spherical Jeans
equation along with measurements of the anisotropic parameter $\beta$ currently
available. The typical uncertainties of RC derived from the PRCG and HKG
samples are respectively 5-7 km/s and several tens km/s. We determine a
circular velocity at the solar position, $V_c (R_0)$ = 240 $\pm$ 6 km/s and an
azimuthal peculiar speed of the Sun, $V_{\odot}$ = 12.1 $\pm$ 7.6 km/s, both in
good agreement with the previous determinations. The newly constructed RC has a
generally flat value of 240 km/s within a Galactocentric distance $r$ of 25 kpc
and then decreases steadily to 150 km/s at $r$ $\sim$ 100 kpc. On top of this
overall trend, the RC exhibits two prominent localized dips, one at $r$ $\sim$
11 kpc and another at $r$ $\sim$ 19 kpc. From the newly constructed RC,
combined with other constraints, we have built a parametrized mass model for
the Galaxy, yielding a virial mass of the Milky Way's dark matter halo of
$0.90^{+0.07}_{-0.08} \times 10^{12}$ ${\rm M}_{\odot}$ and a local dark matter
density, $\rho_{\rm \odot, dm} = 0.32^{+0.02}_{-0.02}$ GeV cm$^{-3}$.
