The Next Generation Fornax Survey (NGFS): VII. A MUSE view of the
  nuclear star clusters in Fornax dwarf galaxies
  Clues to the formation and evolution of Nuclear Star Clusters (NSCs) lie in
their stellar populations. However, these structures are often very faint
compared to their host galaxy, and spectroscopic analysis of NSCs is hampered
by contamination of light from the rest of the system. With the introduction of
wide-field IFU spectrographs, new techniques have been developed to model the
light from different components within galaxies, making it possible to cleanly
extract the spectra of the NSCs and study their properties with minimal
contamination from the light of the rest of the galaxy. This work presents the
analysis of the NSCs in a sample of 12 dwarf galaxies in the Fornax Cluster
observed with MUSE. Analysis of the stellar populations and star-formation
histories reveal that all the NSCs show evidence of multiple episodes of star
formation, indicating that they have built up their mass further since their
initial formation. The NSCs were found to have systematically lower
metallicities than their host galaxies, which is consistent with a scenario for
mass-assembly through mergers with infalling globular clusters, while the
presence of younger stellar populations and gas emission in the core of two
galaxies is indicative of in-situ star formation. We conclude that the NSCs in
these dwarf galaxies likely originated as globular clusters that migrated to
the core of the galaxy which have built up their mass mainly through mergers
with other infalling clusters, with gas-inflow leading to in-situ star
formation playing a secondary role.
