ARE GLOBULAR CLUSTERS THE REMNANT NUCLEI OF PROGENITOR DISK GALAXIES?

摘要

The globular cluster system of a typical spheroidal galaxy makes up about 0.25% of the total galaxy mass. This is roughly the same mass fraction as contained in the nuclear star cluster (or stellar nucleus) present in most nearby low-mass galaxies. Motivated by this "coincidence," this Letter discusses a scenario in which globular clusters of present-day galaxies are the surviving nuclei of the dwarf galaxies that-according to the hierarchical merging paradigm of galaxy formation-constitute the "building blocks" of present-day massive galaxies. This scenario, which was first suggested by Freeman, has become more attractive recently in light of studies that demonstrate a complex star formation history in a number of massive globular clusters.