Merging massive star clusters as building blocks of dwarf galaxies?

Recent spectroscopic observations of galaxies in the Fornax-Cluster reveal nearly unresolved `star-like' objects with red-shifts appropriate to the Fornax-Cluster. These objects have intrinsic sizes of approximate to 100 pc and absolute B-band magnitudes in the range - 14 < M B < -11.5 mag and lower limits for the central surface brightness mu(B) greater than or equal to 23 mag/arcsec(2) (Phillipps et al., 2001, Hilker et al., 1999), and so appear to constitute a new population of ultra-compact dwarf galaxies (UCDs). Such compact dwarfs were predicted to form from the amalgamation of stellar super-clusters (= clusters of star clusters; not to confuse with super stellar clusters (SSC)) by P. Kroupa (1998), which are rich aggregates of young massive star clusters (YMCs) that can form in collisions between gas-rich galaxies. Here we present the evolution of super-clusters in a tidal field. The YMCs merge on a few super-cluster crossing times. Super-clusters that are initially as concentrated and massive as Knot S in the interacting Antennae galaxies (Whitmore et al., 1999) evolve to merger objects that are long-lived and show properties comparable to the newly discovered UCDs.