Evidence for Two Distinct Stellar Initial Mass Functions : Revisiting
  the Effects of Cluster Dynamical Evolution
  We measure the velocity dispersions of six, galactic globular clusters using
spatially integrated spectra, to test for the effects of internal dynamical
evolution in the stellar mass-to-light ratios, Upsilon_*, of star clusters. In
particular, we revisit whether the low values of Upsilon_* we found in our
previous study, from which we concluded that there are at least two population
of stellar clusters with distinct stellar initial mass functions, are
artificially depressed by relaxation driven mass loss. The combination of our
previous sample of five old clusters and these six now provides an order of
magnitude range in cluster mass with which to explore this issue. We find no
relationship between cluster mass, or relaxation time, and Upsilon_*. Because
relaxation is mass dependent, we conclude that the values of Upsilon_* for
these clusters are not strongly affected by dynamical effects, and so confirm
the presence of the population of clusters with low Upsilon_*.
