Effects of coplanar satellite bands on galactic disc evolution
  Small dwarf companions have been long thought to have minimal influence on
their host galaxy's evolution without undergoing direct impacts to the host's
disc. However, in light of recent discoveries of coplanar, corotating satellite
structures around the Milky Way, Andromeda, and Centaurus A, we use an
N-body/test particle simulation to show that low-mass dwarf satellites within
such structures are able to exert significant influence on their host's disc,
driving spiral waves and inducing stellar scattering. This is accomplished
through quasi-periodic alignments of multiple small satellites within the
structure that emulate the gravitational influence of a single, larger
satellite such as Sagittarius Dwarf or the Large Magellanic Cloud. We find that
the coplanar, corotational nature of such structures allows for repeated
alignments on short enough timescales to overcome damping within the disc, and
in a consistent enough fashion to continually drive spiral waves over the
course of 2 Gyr of simulation time. The spirals driven by this phenomenon tend
to be flocculent and many-armed due to the irregular intervals over which
alignments occur. We additionally find that while the aligned satellites are
able to induce noticeable thickening of the disc, their ability to drive
surface density profile evolution is secondary to other effects.
