Wandering Black Holes in Bright Disk Galaxy Halos
  We perform SPH+N-body cosmological simulations of massive disk galaxies,
including a formalism for black hole seed formation and growth, and find that
satellite galaxies containing supermassive black hole seeds are often stripped
as they merge with the primary galaxy. These events naturally create a
population of "wandering" black holes that are the remnants of stripped
satellite cores; galaxies like the Milky Way may host 5 -- 15 of these objects
within their halos. The satellites that harbor black hole seeds are comparable
to Local Group dwarf galaxies such as the Small and Large Magellanic Clouds;
these galaxies are promising candidates to host nearby intermediate mass black
holes. Provided that these wandering black holes retain a gaseous accretion
disk from their host dwarf galaxy, they give a physical explanation for the
origin and observed properties of some recently discovered off-nuclear
ultraluminous X-ray sources such as HLX-1.
