The Impact of Stellar Collisions in the Galactic Center
  We consider whether stellar collisions can explain the observed depletion of
red giants in the Galactic center. We model the stellar population with two
different IMFs: 1) the Miller-Scalo and 2) a much flatter IMF. In the former
case, low-mass main-sequence stars dominate the population, and collisions are
unable to remove red giants out to 0.4 pc although brighter red giants much
closer in may be depleted via collisions with stellar-mass black holes. For a
much flatter IMF, the stellar population is dominated by compact remnants (i.e.
black holes, white dwarfs and neutron stars). The most common collisions are
then those between main-sequence stars and compact remnants. Such encounters
are likely to destroy the main-sequence stars and thus prevent their evolution
into red giants. In this way, the red-giant population could be depleted out to
0.4 pc matching observations. If this is the case, it implies the Galactic
center contains a much larger population of stellar-mass black holes than would
be expected from a regular IMF. This may in turn have implications for the
formation and growth of the central supermassive black hole.
