A Catalog of Globular Cluster Systems: What Determines the Size of a
  Galaxy's Globular Cluster Population?
  We present a catalog of 422 galaxies with published measurements of their
globular cluster (GC) populations. Of these, 248 are E galaxies, 93 are S0
galaxies, and 81 are spirals or irregulars. Among various correlations of the
total number of GCs with other global galaxy properties, we find that N_GC
correlates well though nonlinearly with the dynamical mass of the galaxy bulge
M_dyn = 4 \sigma_e^2 R_e /G, where \sigma_e is the central velocity dispersion
and R_e the effective radius of the galaxy light profile. We also present
updated versions of the GC specific frequency S_N and specific mass S_M versus
host galaxy luminosity and baryonic mass. These graphs exhibit the previously
known U-shape: highest S_N or S_M values occur for either dwarfs or
supergiants, but in the midrange of galaxy size (10^9 - 10^10 L_Sun) the GC
numbers fall along a well defined baseline value of S_N ~ 1 or S_M ~ 0.1,
similar among all galaxy types. Along with other recent discussions, we suggest
that this trend may represent the effects of feedback, which systematically
inhibited early star formation at either very low or very high galaxy mass, but
which had its minimum effect for intermediate masses. Our results strongly
reinforce recent proposals that GC formation efficiency appears to be most
nearly proportional to the galaxy halo mass M_halo. The mean "absolute"
efficiency ratio for GC formation that we derive from the catalog data is
M_GCS/M_halo = 6 \times 10^-5. We suggest that the galaxy-to-galaxy scatter
around this mean value may arise in part because of differences in the relative
timing of GC formation versus field-star formation. Finally, we find that an
excellent empirical predictor of total GC population for galaxies of all
luminosities is N_GC \sim (R_e \sigma_e)^1.3$, a result consistent with
Fundamental Plane scaling relations.
