Chemical Cartography. II. The Assembly History of the Galactic Stellar
  Halo Traced by Carbon-Enhanced Metal-Poor Stars
  We present an analysis of the kinematic properties of stellar populations in
the Galactic halo, making use of over 100,000 main sequence turnoff (MSTO)
stars observed in the Sloan Digital Sky Survey. After dividing the Galactic
halo into an inner-halo region (IHR) and outer-halo region (OHR), based on the
spatial variation of carbon-to-iron ratios in the sample, we find that stars in
the OHR exhibit a clear retrograde motion of $-$49 $\pm$ 4 km s$^{-1}$ and a
more spherical distribution of stellar orbits, while stars in the IHR have zero
net rotation ($-$3 $\pm$ 1 km s$^{-1}$) with a much more radially biased
distribution of stellar orbits. Furthermore, we classify the carbon-enhanced
metal-poor (CEMP) stars among the MSTO sample in each halo component into
CEMP-no and CEMP-$s$ sub-classes, based on their absolute carbon abundances,
$A$(C), and examine the spatial distributions and kinematics associated with
each sub-class. The CEMP-no stars are the majority sub-class of CEMP stars in
the OHR ($\sim$ 65%), and the minority sub-class in the IHR ($\sim$ 44%),
similar to the results of several previous analyses. The CEMP-no stars in each
halo region exhibit slightly higher counter-rotation than the CEMP-$s$ stars,
but within statistical errors. The CEMP-no stars also show a more spherical
distribution of orbits than the CEMP-$s$ stars in each halo region. These
distinct characteristics provide strong evidence that numerous low-mass
satellite galaxies (similar to the ultra-faint dwarf galaxies) have donated
stars to the OHR, while more-massive dwarf galaxies provided the dominant
contribution to the IHR.
