Measuring Dark Matter Profiles Non-Parametrically in Dwarf Spheroidals:
  An Application to Draco
  We introduce a novel implementation of orbit-based (or Schwarzschild)
modeling that allows dark matter density profiles to be calculated
non-parametrically in nearby galaxies. Our models require no assumptions to be
made about velocity anisotropy or the dark matter profile. The technique can be
applied to any dispersion-supported stellar system, and we demonstrate its use
by studying the Local Group dwarf spheroidal (dSph) galaxy Draco. We use
existing kinematic data at larger radii and also present 12 new radial
velocities within the central 13 pc obtained with the VIRUS-W integral field
spectrograph on the 2.7m telescope at McDonald Observatory. Our non-parametric
Schwarzschild models find strong evidence that the dark matter profile in Draco
is cuspy for 20 < r < 700 pc. The profile for r > 20 pc is well-fit by a power
law with slope \alpha=-1.0 +/- 0.2, consistent with predictions from Cold Dark
Matter (CDM) simulations. Our models confirm that, despite its low baryon
content relative to other dSphs, Draco lives in a massive halo.
