From a star cluster ensemble to its formation history

摘要

The present-day sample of ultra-compact dwarf galaxies (UCDs) and globular clusters (GCs) around NGC 1399 is interpreted to be composed of individual star cluster (SC) populations. It is assumed that such an SC population forms at a constant star-formation rate (SFR), and its mass distribution is described by the embedded cluster mass function (ECMF) up to the upper limit M_(max). The GCs and UCDs probably formed in interactions of the progenitor galaxies during the assembly of the central Fornax galaxy cluster which is why we use them as tracers of those events. After some corrections, the overall GC/UCD mass function is decomposed into separate SC populations, each described by an ECMF. M_(max) of each ECMF is converted to an SFR according to the SFR-M_(max) relation, revealing the SFRs reached during the assembly of galaxies in the central Fornax galaxy cluster.