Galactic substructure traced by RR Lyraes in SDSS Stripe 82
  Using a sample of 407 RR Lyrae stars extracted from SDSS Stripe 82, we study
the degree of substructure in the Galactic halo. We identify overdensities
associated with the known substructures of the Hercules-Aquila Cloud and the
Sagittarius Stream, and find a further previously-unknown substructure, the
Pisces Overdensity, at ~100 kpc from the Sun. Together, the three substructures
account for ~80% of our RR Lyrae sample. We also study the density distribution
of RR Lyraes in the halo and find that the profile is best fit by a broken
power law with an inner slope of -2.4 and a break radius of ~25 kpc, consistent
with previous studies. We conclude that the halo is predominantly made up of
the debris from in-falling satellites, with little or no underlying smooth
component.
