Formation of Globular Cluster Systems: From Dwarf Galaxies to Giants

Understand

Globular cluster (GC) systems around galaxies of a vast mass range show remarkably simple scaling relations.

• The combined mass of all GCs is a constant fraction of the total galaxy mass and the mean metallicity and metallicity dispersion of the GC system scale up weakly with galaxy mass.
• The metallicity of massive, metal-poor ("blue") clusters increases with cluster mass, while that of metal-rich ("red") clusters does not.
• A significant age-metallicity relation emerges from analysis of resolved stellar populations in Galactic GCs and unresolved populations in nearby galaxies.