Extragalactic Globular Cluster Systems: A new Perspective on Galaxy Formation and Evolution

We present an overview of observational progress in the study of extragalactic globular cluster systems. Globular clusters turn out to be excellent tracers not only for the star-formation histories in galaxies, but also for kinematics at large galactocentric radii. Their properties can be used to efficiently constrain galaxy formation and evolution. After a brief introduction of the current methods and futures perspectives, we summarize the knowledge gained in various areas of galaxy research through the study of globular clusters. In particular, we address the star-formation histories of early-type galaxies; globular cluster population in late-type galaxies and their link to early-type galaxies; star and cluster formation during mergers and violent interactions; and the kinematics at large radii in early-type galaxies. The different points are reviewed within the context of galaxy formation and evolution. Finally, we revisit the globular cluster luminosity function as a distance indicator. Despite its low popularity in the literature, we demonstrate that it ranks among one of the most precise distance indicators to early-type galaxies, provided that it is applied properly.