Nuclear Star Clusters from groups to clusters: the role of environment in the increased nucleation of dwarf galaxies in massive environments


Horário de início



Auditório 2 - P218 – IAG/USP (Rua do Matão, 1226 - Cidade Universitária)

Abstract: Nuclear star clusters (NSCs) can be found at the centre of galaxies of a wide variety of masses and morphologies. Investigating their occupation statistics in different environments provides an invaluable window to investigate early conditions of high-density star formation and mass assembly in groups and clusters of galaxies. In this talk, I will present our work on this topic regarding two of the most massive nearby mass concentrations of the Universe: the Coma Cluster and the Shapley Supercluster. Using deep HST imaging, we investigate the NSC occurrence in quiescent dwarf galaxies and compare it with all other environments where nucleation data is available. Then we employ a Hierarchical Bayesian Logistic Regression framework to model the galaxy nucleation fraction as a function of luminosity and environment. Our results show that, at a fixed magnitude, galaxies in more massive environments are more likely to host NSCs. This is not predicted by the most accepted NSC formation models, but I will present the current discussion on this issue in the literature. Furthermore, I will raise awareness of the necessity to employ robust statistical approaches in studying galaxy occupation fractions, specially avoiding binning methodologies.

Mini-bio:  Emilio Zanatta obteve formação em Física pela Universidade Federal de Juiz de Fora (UFJF), mestrado e doutorado em Astrofísica pela Universidade Federal do Rio Grande do Sul (UFRGS). Atualmente é Pós-Doutorando no IAG/USP, investigando a evolução de galáxias através de seus aglomerados estelares.  

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