Tidal tails of dwarf galaxies on different orbits around the Milky Way
  We present a phenomenological description of the properties of tidal tails
forming around dwarf galaxies orbiting the Milky Way. For this purpose we use
collisionless N-body simulations of dwarfs initially composed of a disk
embedded in an NFW dark matter halo. The dwarfs are placed on seven orbits
around the Milky Way-like host, differing in size and eccentricity, and their
evolution is followed for 10 Gyr. In addition to the well-studied morphological
and dynamical transformation of the dwarf's main body, the tidal stripping
causes them to lose a substantial fraction of mass both in dark matter and
stars which form pronounced tidal tails. We focus on the properties of the
stellar component of the tidal tails thus formed. We first discuss the break
radii in the stellar density profile defining the transition to tidal tails as
the radii where the profile becomes shallower and relate them to the
classically defined tidal radii. We then calculate the relative density and
velocity of the tails at a few break radii as a function of the orbital phase.
Next, we measure the orientation of the tails with respect to an observer
placed at the centre of the Milky Way. The tails are perpendicular to this line
of sight only for a short period of time near the pericentre. For most of the
time the angles between the tails and this line of sight are low, with
orbit-averaged medians below 42 degrees for all, even the almost circular
orbit. The median angle is typically lower while the maximum relative density
higher for more eccentric orbits. The combined effects of relative density and
orientation of the tails suggest that they should be easiest to detect for
dwarf galaxies soon after their pericentre passage.
