2016ApJ...818...99Z

Using 3.6 and 4.5 µm images of 73 late-type, edge-on galaxies from the S⁴G survey, we compare the richness of the globular cluster populations of these galaxies to those of early-type galaxies that we measured previously. In general, the galaxies presented here fill in the distribution for galaxies with lower stellar mass, M_*, specifically log(M_*/M_☉ < 10, overlap the results for early-type galaxies of similar masses, and, by doing so, strengthen the case for a dependence of the number of globular clusters per 10⁹M_☉ of galaxy stellar mass, T_N, on M_*. For 8.5 < log(M_*/M_☉ < 10.5 we find the relationship can be satisfactorily described as T_N = (M_*/10^6.7)^–0.56 when M_*is expressed in solar masses. The functional form of the relationship is only weakly constrained, and extrapolation outside this range is not advised. Our late-type galaxies, in contrast to our early types, do not show the tendency for low-mass galaxies to split into two T_Nfamilies. Using these results and a galaxy stellar mass function from the literature, we calculate that, in a volume-limited, local universe sample, clusters are most likely to be found around fairly massive galaxies (M_*∼ 10^10.8M_☉) and present a fitting function for the volume number density of clusters as a function of parent-galaxy stellar mass. We find no correlation between T_N and large-scale environment, but we do find a tendency for galaxies of fixed M_*to have larger T_Nif they have converted a larger proportion of their baryons into stars.