A Comparison Between the Half-Light Radii, Luminosities, and UBV Colors
  of Globular Clusters in M31 and the Galaxy
  The Milky Way System and the Andromeda galaxy experienced radically different
evolutionary histories. Nevertheless, it is found that these two galaxies ended
up with globular cluster systems in which individual clusters have
indistinguishable distributions of half-light radii. Furthermore globulars in
both M31 and the Galaxy are found to have radii that are independent of their
luminosities. In this respect globular clusters differ drastically from
early-type galaxies in which half-light radius and luminosity are tightly
correlated. Metal-rich globular clusters in M31 occupy a slightly larger volume
than do those in the Galaxy. The specific globular cluster frequency in the
Andromeda galaxy is found to he significantly higher than it is in the Milky
Way System. The present discussion is based on the 107 Galactic globular
clusters, and 200 putative globulars in M31, for which UBV photometry was
available.
