Intra Cluster Globular Clusters around NGC 1399 in Fornax?

TL;DR

This study examines the nature of globular clusters in the Fornax cluster, determining their association with host galaxies or as intra-cluster objects, using velocity data and photometry.

Contribution

It provides evidence that most metal-poor GCs are part of NGC 1399's extended system, clarifying their intra-cluster or galaxy-bound status.

Findings

Most metal-poor GCs are consistent with NGC 1399 membership.

Metal-rich GCs are associated with their host galaxies.

Identified one potential intra-cluster 'vagrant' GC.

Abstract

We investigate whether the globular clusters (GCs) in the recently published sample of GCs in the Fornax cluster by Bergond and coworkers are indeed intra-cluster objects. We combine the catalogue of radial velocity measurements by Bergond et al. with our CTIO MOSAIC photometry in the Washington system and analyse the relation of metal-poor and metal-rich GCs with their host galaxies. The metal-rich GCs appear to be kinematically associated with their respective host galaxies. The vast majority of the metal-poor GCs found in between the galaxies of the Fornax cluster have velocities which are consistent with them being members of the very extended NGC 1399 GC system. We find that when the sample is restricted to the most accurate velocity measurements, the GC velocity dispersion profile can be described with a mass model derived for the NGC 1399 GC system within 80 kpc. We identify one ``vagrant'' GC whose radial velocity suggests that it is not bound to any galaxy unless its orbit has a very large apogalactic distance.