A Spatial Characterization of the Sagittarius Dwarf Galaxy Tidal Tails
  We measure the spatial density of F turnoff stars in the Sagittarius dwarf
tidal stream, from Sloan Digital Sky Survey (SDSS) data, using statistical
photometric parallax. We find a set of continuous, consistent parameters that
describe the leading Sgr stream's position, direction, and width for 15 stripes
in the North Galactic Cap, and 3 stripes in the South Galactic Cap. We produce
a catalog of stars that has the density characteristics of the dominant leading
Sgr tidal stream that can be compared with simulations. We find that the width
of the leading (North) tidal tail is consistent with recent triaxial and
axisymmetric halo model simulations. The density along the stream is roughly
consistent common disruption models in the North, but possibly not in the
South. We explore the possibility that one or more of the dominant Sgr streams
has been mis-identified, and that one or more of the `bifurcated' pieces is the
real Sgr tidal tail, but we do not reach definite conclusions. If two dwarf
progenitors are assumed, fits to the planes of the dominant and `bifurcated'
tidal tails favor an association of the Sgr dwarf spheroidal galaxy with the
dominant Southern stream and the `bifurcated' stream in the North. In the North
Galactic Cap, the best fit Hernquist density profile for the smooth component
of the stellar halo is oblate, with a flattening parameter q = 0.53, and a
scale length of r_0 = 6.73. The Southern data for both the tidal debris and the
smooth component of the stellar halo do not match the model fits to the North,
although the stellar halo is still overwhelmingly oblate. Finally, we verify
that we can reproduce the parameter fits on the asynchronous Milkyway@home
volunteer computing platform.
