NGC 5128 GCs from PISCes, Gaia DR2 and NSC

Ranking these candidates based on the likelihood that they are true GCs, we find that approximately 1900 belong to our top two ranking categories and should be the highest priority for spectroscopic follow-up for confirmation.

Taking into account our new data and a vetting of previous GC catalogs, we estimate a total GC population of 1450+/-160 GCs. We show that a substantial number of sources previously argued to be low-velocity GCs are instead foreground stars, reducing the inferred GC velocity dispersion. This work showcases the power of Gaia to identify slightly extended sources at the ~4Mpc distance of NGC 5128, enabling accurate identification of GCs throughout the entire extended halo, not just the inner regions that have been the focus of most previous work.