Dispersal of tidal debris in a Milky-Way-sized dark matter halo
  We simulate the tidal disruption of a collisionless N-body globular star
cluster in a total of 300 different orbits selected to have galactocentric
radii between 10 and 30 kpc in four dark matter halos: (a) a spherical halo
with no subhalos, (b) a spherical halo with subhalos, (c) a realistic halo with
no subhalos, and (d) a realistic halo with subhalos. This allows us to isolate
and study how the halo's (lack of) dynamical symmetry and substructures affect
the dispersal of tidal debris. The realistic halos are constructed from the
snapshot of the Via Lactea II simulation at redshift zero. We find that the
overall halo's lack of dynamical symmetry disperses tidal debris to make the
streams fluffier, consistent with previous studies of tidal debris of dwarf
galaxies in larger orbits than ours in this study. On the other hand, subhalos
in realistic potentials can locally enhance the densities along streams, making
streams denser than their counterparts in smooth potentials. We show that many
long and thin streams can survive in a realistic and lumpy halo for a Hubble
time. This suggests that upcoming stellar surveys will likely uncover more thin
streams which may contain density gaps that have been shown to be promising
probes for dark matter substructures.
