Stellar Substructures around the Hercules Dwarf Spheroidal Galaxy
  We present deep $g,i$-band DECam stellar photometry of the Hercules Milky Way
satellite galaxy, and its surrounding field, out to a radial distance of 5.4
times the tidal radius. We have identified nine extended stellar substructures
associated with the dwarf; preferentially distributed along the major axis of
the galaxy. Two significant over-densities lie outside the 95\% confidence band
for the likely orbital path of the galaxy and appear to be free-floating tidal
debris. We estimate the luminosity of the new stellar substructures, and find
that approximately the same amount of stellar flux is lying in these extended
structures as inside the main body of Hercules. We also analyse the
distribution of candidate blue-horizontal-branch stars and find agreement with
the alignment of the substructures at a confidence level greater than 98\%. Our
analysis provides a quantitative demonstration that Hercules is a strongly
tidally disrupted system, with noticeable stellar features at least 1.9 kpc
away from the galaxy.
