Dark influences: imprints of dark satellites on dwarf galaxies
  In the context of the current $\Lambda$CDM cosmological model small dark
matter haloes are abundant and satellites of dwarf galaxies are expected to be
predominantly dark. Since low mass galaxies have smaller baryon fractions
interactions with these satellites may leave particularly dramatic imprints. We
uncover the influence of the most massive of these dark satellites on disky
dwarf galaxies and the possible dynamical and morphological transformations
that result from these interactions. We use a suite of carefully set-up,
controlled simulations of isolated dwarf galaxies. The primary dwarf galaxies
have solely a stellar disk in the dark matter halo and the secundaries are
completely devoid of baryons. We vary the disk mass, halo concentration,
initial disk thickness and inclination of the satellite orbit. The disky dwarf
galaxies are heated and disrupted due to the minor merger event, more extremely
for higher satellite over disk mass ratios, and the morphology and kinematics
are significantly altered. Moreover, for less concentrated haloes the minor
merger can completely destroy the disk leaving a low-luminosity spheroidal-like
galaxy instead. We conclude that dwarf galaxies are very much susceptible to
being disturbed by dark galaxies and that even a minor merger event can
significantly disrupt and alter the structure and kinematics of a dwarf galaxy.
This process may be seen as a new channel for the formation of dwarf spheroidal
galaxies.
