  We present a detailed comparison between the latest observational data on the
kinematical structure of the core of M15, obtained with the Hubble STIS and
WFPC2 instruments, and the results of dynamical simulations carried out using
the special-purpose GRAPE-6 computer. The observations imply the presence of a
significant amount of dark matter in the cluster core. In our dynamical
simulations, neutron stars and/or massive white dwarfs concentrate to the
center through mass segregation, resulting in a sharp increase in $M/L$ toward
the center. While consistent with the presence of a central black hole, the
Hubble data can also be explained by this central concentration of stellar-mass
compact objects. The latter interpretation is more conservative, since such
remnants result naturally from stellar evolution, although runaway merging
leading to the formation of a black hole may also occur for some range of
initial conditions. We conclude that no central massive object is required to
explain the observational data, although we cannot conclusively exclude such an
object at the level of $\sim500-1000$ solar masses. Our findings are unchanged
when we reduce the assumed neutron-star retention fraction in our simulations
from 100% to 0%.
