Nuclear Star Clusters
  The centers of most galaxies in the local universe are occupied by compact,
barely resolved sources. Based on their structural properties, position in the
fundamental plane, and integrated spectra, these sources clearly have a stellar
origin. They are therefore called "nuclear star clusters" (NCs) or "stellar
nuclei". NCs are found in galaxies of all Hubble types, suggesting that their
formation is intricately linked to galaxy evolution. Here, I review some recent
studies of NCs, describe ideas for their formation and subsequent growth, and
touch on their possible evolutionary connection with both supermassive black
holes and globular clusters.
