Plan beta: Core or Cusp?
  The inner profile of Dark Matter (DM) halos remains one of the central
problems in small-scale cosmology. At present, the problem can not be resolved
in dwarf spheroidal galaxies due to a degeneracy between the DM profile and the
velocity anisotropy beta of the stellar population. We discuss a method which
can break the degeneracy by exploiting 3D positions and 1D line-of-sight (LOS)
velocities. With the full 3D spatial information, we can determine precisely
what fraction of each stars LOS motion is in the radial and tangential
direction. This enables us to infer the anisotropy parameter beta directly from
the data. The method is particularly effective if the galaxy is highly
anisotropic. Finally, we argue that such a test could be applied to Sagittarius
and potentially other dwarfs with RR Lyrae providing the necessary depth
information.
