Dynamical friction and scratches of orbiting satellite galaxies on host
  systems
  We study the dynamical response of extended systems, hosts, to smaller
systems, satellites, orbiting around the hosts using extremely high-resolution
N-body simulations with up to one billion particles. This situation corresponds
to minor mergers which are ubiquitous in the scenario of hierarchical structure
formation in the universe. According to Chandrasekhar (1943), satellites create
density wakes along the orbit and the wakes cause a deceleration force on
satellites, i.e. dynamical friction. This study proposes an analytical model to
predict the dynamical response of hosts as reflected in their density
distribution and finds not only traditional wakes but also mirror images of
over- and underdensities centered on the host. Our controlled N-body
simulations with high resolutions verify the predictions of the analytical
model. We apply our analytical model to the expected dynamical response of
nearby interacting galaxy pairs, the Milky Way - Large Magellanic Cloud system
and the M31 - M33 system.
