Nuclear Star Clusters in Cosmological Simulations
  We investigate the possible connection between the most massive globular
clusters, such as $\omega$ Cen and M54, and nuclear star clusters of dwarf
galaxies that exhibit similar spreads in age and metallicity. We examine
galactic nuclei in cosmological galaxy formation simulations at $z \approx 1.5$
to explore whether their age and metallicity spreads could explain these
massive globular clusters. We derive structural properties of these nuclear
regions, including mass, size, rotation, and shape. By using theoretical
supernova yields to model the supernova enrichment in the simulations, we
obtain individual elemental abundances for Fe, O, Na, Mg, and Al. Our nuclei
are systematically more metal-rich than their host galaxies, which lie on the
expected mass-metallicity relation. Some nuclei have a spread in Fe and age
comparable to the massive globular clusters of the Milky Way, lending support
to the hypothesis that nuclear star clusters of dwarf galaxies could be the
progenitors of these objects. None of our nuclear regions contain the light
element abundance spreads that characterize globular clusters, even when a
large age spread is present. Our results demonstrate that extended star
formation history within clusters, with metal pollution provided solely by
supernova ejecta, is capable of replicating the metallicity spreads of massive
globular clusters, but still requires another polluter to produce the light
element variations.
