The Lost Dwarfs of Centaurus A and the Formation of its Dark Globular
  Clusters
  We present theoretical constraints for the formation of the newly discovered
dark star clusters (DSCs) with high mass-to-light (M/L) ratios, from Taylor et
al (2015). These compact stellar systems photometrically resemble globular
clusters (GCs) but have dynamical M/L ratios of ~ 10 - 100, closer to the
expectations for dwarf galaxies. The baryonic properties of the dark star
clusters (DSCs) suggest their host dark matter halos likely virialized at high
redshift with M > 10^8 M_sun. We use a new set of high-resolution N-body
simulations of Centaurus A to determine if there is a set of z=0 subhalos whose
properties are in line with these observations. While we find such a set of
subhalos, when we extrapolate the dark matter density profiles into the inner
20 pc, no dark matter halo associated with Centaurus A in our simulations, at
any redshift, can replicate the extremely high central mass densities of the
DSCs. Among the most likely options for explaining 10^5 - 10^7 M_sun within 10
pc diameter subhalos is the presence of a central massive black hole. We,
therefore, propose that the DSCs are remnant cusps of stellar systems
surrounding the central black holes of dwarf galaxies which have been almost
completely destroyed by interactions with Centaurus A.
