Subhalo sinking and off-center massive black holes in dwarf galaxies
  Using fully GPU $N$-body simulations, we demonstrate for the first time that
subhalos sink and transfer energy via dynamical friction into the centres of
dwarf galaxies. This dynamical heating kicks any central massive black hole
(MBH) out to tens of parsecs, especially at early epochs ($z$=1.5-3). This
mechanism helps explain the observed off-center BHs in dwarf galaxies and also
predicts that off-center BHs are more common in higher mass dwarf galaxies
since dynamical friction becomes significantly weaker and BHs take more time to
sink back towards the centres of their host galaxies. One consequence of
off-center BHs during early epochs of dwarf galaxies is to quench any BH
feedback.
