The ACS Virgo Cluster Survey. XV. The Formation Efficiencies of Globular Clusters in Early‐Type Galaxies: The Effects of Mass and Environment
The fraction of stellar mass contained in globular clusters (GCs), also measured by number as the specific frequency, is a fundamental quantity that reflects both a galaxy’s early star formation and its entire merging history. We present specific frequencies, luminosities, andmass fractions for the globular cluster systems of 100 early-type galaxies in the ACSVirgo Cluster Survey, the largest homogeneous catalog of its kind.We find the following: (1) GCmass fractions can be high in both giants and dwarfs but are universally low in galaxies with intermediate luminosities. (2) The be-havior of specific frequency across galaxy mass is dominated by the blue GCs. (3) GC fractions of low-mass galaxies exhibit a dependence on environment. Nearly all dwarf galaxies with high GC fractions are within 1 Mpc of the cD galaxy M87, presenting the first strong evidence that GC formation in dwarfs is biased toward dense environments. (4) GC formation in central dwarfs is biased because their stars form earliest and most intensely. Comparisons to the