  Recent images taken with the Hubble Space Telescope (HST) of the interacting
disk galaxies NGC 4038/4039 (the Antennae) reveal clusters of many dozens and
possibly hundreds of young compact massive star clusters within projected
regions spanning about 100 to 500 pc. It is shown here that a large fraction of
the individual star clusters merge within a few tens to a hundred Myr. Bound
stellar systems with radii of a few hundred pc, masses of less than about 10^9
Msun and relaxation times of 10^{11}-10^{12} yr may form from these. These
spheroidal dwarf galaxies contain old stars from the pre-merger galaxy and much
younger stars formed in the massive star clusters, and possibly from later
gas-accretion events. The possibility that star formation in the outer regions
of gas-rich tidal tails may also lead to super clusters is raised. The
mass-to-light ratio of these objects is small, because they contain an
insignificant amount of dark matter. After many hundred Myr such systems may
resemble dwarf spheroidal satellite galaxies with large apparent mass-to-light
ratia, if tidal shaping is important.
