Globular cluster systems as guides on the host-galaxy evolution: peculiar versus standard properties

ENNIS A.I.; BASSINO L. P.; DE BORTOLI B.J.; CASO J. P

Bologna

Simposio; Simposio 351 de la IAU: Star Clusters: from the Milky Way to the Early Universe; 2019

Union Astronomica Internacional - INAF (Italia)

It is wellknown that globular cluster systems (GCSs) carry information related to theformation and evolution of their host-galaxies. Although those associated withearly-type galaxies mostly show similar characteristics, like the existence oftwo globular cluster (GC) subpopulations, in the past years several GCSs havebeen detected whose properties differ from the "standard" ones (e.g.the presence of a third GC subpopulation with colors between those of typicalmetal-poor and metal-rich GCs, anomalies in the GC luminosity function, etc.).We have studied several cases in which these "peculiar" properties ofthe GCS, usually combined with characteristics of the host-galaxy, may berelated to bursts of star formation and help to reconstruct the history of thehost-galaxy.In the study of NGC 3610 (Bassino et al. 2017), a prototype of anintermediate-age merger remnant, we confirmed the presence of a clustersubpopulation with "intermediate" colors in the outskirts, apparentlyassociated to the rich fine structure present in the galaxy surface-brightnessdistribution, that may have originated in such disk-disk merger.  Furthermore, in the GCS of the isolated galaxy NGC 6411 (Caso et al. 2019), wedetected an excess of bright GCs in the luminosity function, with"intermediate" colors and concentrated towards the galaxy, thatsuggest an intermediate-age wet merger, older than the diffuse stellarpopulation of the inner galaxy. Finally, we have recently analyzed the GCS of NGC 6876 (Ennis et al.,submitted) where the metal-rich GC  subpopulation shows an overdensity inthe azimuthal projected distribution in the same direction as an X-ray trail towardsits large spiral neighbor NGC 6872, that could be evidence of pastinteractions.