The specific frequency of globular clusters in galaxies

Abstract

Variations in the number of globular clusters per unit galaxy luminosity, which is the specific frequency, and the mass of globular clusters per unit total available mass, are reviewed. Correlations with galaxy luminosity and morphology, and with the properties of the associated galactic clusters are discussed, as are the color distributions of globular cluster populations. Several models for the origin of these variations are summarized, including the tidal stripping and interaction/starburst models. Most of the variations in the specific frequency for elliptical galaxies result from variations in the ratio of total mass to light with a nearly constant efficiency for conversion of gas into globular cluster mass. Smaller additional variations may come from tidal stripping, particularly in cD galaxies.