Searching in the dark: the dark mass content of the Milky Way globular
  clusters NGC288 and NGC6218
  We present an observational estimate of the fraction and distribution of dark
mass in the innermost region of the two Galactic globular clusters NGC 6218
(M12) and NGC 288. Such an assessment has been made by comparing the dynamical
and luminous mass profiles derived from an accurate analysis of the most
extensive spectroscopic and photometric surveys performed on these stellar
systems. We find that non-luminous matter constitutes more than 60% of the
total mass in the region probed by our data (R<1.6 arcmin~r_h) in both
clusters. We have carefully analyzed the effects of binaries and tidal heating
on our estimate and ruled out the possibility that our result is a spurious
consequence of these effects. The dark component appears to be more
concentrated than the most massive stars suggesting that it is likely composed
of dark remnants segregated in the cluster core.
