A 2MASS All-Sky View of the Sagittarius Dwarf Galaxy: VII. Kinematics of
  the Main Body of the Sagittarius dSph
  We have assembled a large-area spectroscopic survey of giant stars in the
Sagittarius (Sgr) dwarf galaxy core. Using medium resolution (R ~15,000),
multifiber spectroscopy we have measured velocities of these stars, which
extend up to 12 degrees from the galaxy's center (3.7 core radii or 0.4 times
the King limiting radius). From these high quality spectra we identify 1310 Sgr
members out of 2296 stars surveyed distributed across 24 different fields
across the Sgr core. Additional slit spectra were obtained of stars bridging
from the Sgr core to its trailing tail. Our systematic, large area sample shows
no evidence for significant rotation, a result at odds with the ~20 km/s
rotation required as an explanation for the bifurcation seen in the Sgr tidal
stream; the observed small (<= 4 km/s) velocity trend along primarily the major
axis is consistent with models of the projected motion of an extended body on
the sky with no need for intrinsic rotation. The Sgr core is found to have a
flat velocity dispersion (except for a kinematically colder center point)
across its surveyed extent and into its tidal tails, a property that matches
the velocity dispersion profiles measured for other Milky Way dwarf spheroidal
(dSph) galaxies. We comment on the possible significance of this observed
kinematical similarity for the dynamical state of the other classical Milky Way
dSphs in light of the fact that Sgr is clearly a strongly tidally disrupted
system.
