On the Origin of Globular Clusters in Elliptical and cD Galaxies

Perhaps the most noteworthy of recent findings in extragalactic globular cluster (GC) research are the multimodal GC metallicity distributions seen in massive early–type galaxies. We explore the origin of these distinct GC populations, the implications for galaxy formation and evolution, and identify several new properties of GC systems. First, when we separate the metal–rich and metal–poor subpopulations, in galaxies with bimodal GC metallicity distributions, we find that the mean metallicity of the metal–rich GCs correlates well with parent galaxy luminosity but the mean metallicity of the metal–poor ones does not. This indicates that the metal–rich GCs are closely coupled to the galaxy and