The Stellar Halo and Tidal Streams of Messier 63
  We present new near-infrared (NIR) observations of M63 from the Extended Disk
Galaxy Exploration Science (EDGES) Survey. The extremely deep 3.6 $\mu$m mosaic
reaches 29 AB mag arcsec$^{-2}$ at the outer reaches of the
azimuthally-averaged surface brightness profile. At this depth the consequences
of galactic accretion are found within a nearby tidal stream and an up-bending
break in the slope of the surface brightness profile. This break occurs at a
semi-major axis length of $\sim$8', and is evidence of either an enhanced outer
disc or an inner stellar halo. Simulations of galaxy evolution, along with our
observations, support an inner halo as the explanation for the up-bending
break. The mass of this halo component is the largest found in an individual
galaxy thus far. Additionally, our observations detect a nearby tidal stream.
The mass of the stream suggests that a handful of such accretion events are
necessary to populate the inner stellar halo. We also find that the accretion
rate of the galaxy from the stream alone underestimates the accretion rate
required to build M63's inner stellar halo.
