  We present the first clear evidence for an extended dark matter halo in the
Draco dwarf spheroidal galaxy based on a sample of new radial velocities for
159 giant stars out to large projected radii. Using a two parameter family of
halo models spanning a range of density profiles and velocity anisotropies, we
are able to rule out (at about the 2.5 sigma confidence level) haloes in which
mass follows light. The data strongly favor models in which the dark matter is
significantly more extended than the visible dwarf. However, haloes with
harmonic cores larger than the light distribution are also excluded. When
combined with existing measurements of the proper motion of Draco, our data
strongly suggest that Draco has not been tidally truncated within ~1 kpc. We
also show that the rising velocity dispersion at large radii represents a
serious problem for modified gravity (MOND).
