The Globular Cluster Systems of Virgo Cluster Dwarf Galaxies

The number of globular cluster (GC) satellites per unit host galaxy luminosity, the GC specific frequency, is not simply a function of host galaxy mass. This is especially true for low-mass dwarf galaxies. While some dwarf galaxies have among the highest GC specific frequencies of any galaxy, others of similar mass have no detectable GCs at all. Understanding this wide variety of GC system properties requires a systematic study of GCs in a large number of low-mass galaxies. The Virgo cluster is the nearest galaxy cluster, and is the largest concentration of dwarf galaxies in the nearby Universe, making it an ideal target for such a study. We present early results from a study of GCs in Virgo cluster dwarf galaxies using deep wide field Canada-France-Hawai’i Telescope (CFHT) MegaCam imaging in the u*g'i'z' bands from the Next Generation Virgo Cluster Survey (NGVS). Because the spatial distribution of GC satellites in host dwarf galaxies is similar to that of their field stars, it is important to properly subtract the integrated smooth galaxy light when searching for GCs. We generate our catalog of color-selected GC candidates from model-subtracted galaxy images, and characterize the completeness of our GC sample in these regions using artificial star tests. We present GC specific frequencies for a sample of Virgo dwarfs and examine trends with mass, morphology, and cluster environment.

NT, BN, and TK conducted their research under the auspices of the Science Internship Program (SIP) at the University of California Santa Cruz.