Diversity of nuclear star cluster formation mechanisms revealed by their star formation histories

Nuclear star clusters (NSCs) are the densest stellar systems in Universe and found centres of all types galaxies. They thought to form via mergers such as ancient globular (GCs) that spiral centre a result dynamical friction or through situ formation directly at galaxy centre. There is evidence both paths occur, but relative contribution either channel their correlation with properties not yet constrained observationally. Our aim was derive dominant NSC for sample 25 nucleated galaxies, mostly Fornax cluster, masses between M gal ∼ 10 8 10.5 ⊙ 5 8.5 . Using Multi-Unit Spectroscopic Explorer data from 3D survey ESO archive, we derived histories, mean ages, metallicities NSCs, compared them host In many low-mass NSCs significantly more metal poor than hosts, similar GCs. contrast, massive galaxies find diverse histories cases ongoing recent formation. Massive (> 7 ) occupy different region mass–metallicity diagram lower-mass GCs, indicating enrichment history. We clear transition mass. hypothesise while GC accretion forms dwarf central responsible efficient mass build up most our sample. At intermediate channels can contribute. The these seems occur 9