Séminaire/Seminar Galaxies |
| « The orbits of galaxies in clusters » |
|
Andrea Biviano |
| Knowledge of how the galaxies orbit in their clusters is important to understand the assembly process of clusters and the evolutionary processes of their galaxies, and to improve the determination of cluster masses based on cluster kinematics. The orbital distribution of galaxies in clusters can be inferred from the cluster velocity anisotropy profiles, beta(r). By solving the Jeans equation for dynamical equilibrium, we determine beta(r) of nine massive clusters at redshift 0.19-0.45 from the CLASH-VLT data set, with 150 to 950 spectroscopic members each. We thus define the mean orbital distribution of galaxies in clusters, and how much this distribution varies from cluster to cluster. To find the cause of the cluster-to-cluster variance in beta(r) we compare our results with results at lower redshifts from the literature, and with numerical simulations. We find that the orbital distribution of cluster galaxies carries information on the merging history of the clusters. |
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jeudi 20 novembre 2025 - 11:30 Salle Entresol Daniel Chalonge Institut d'Astrophysique de Paris |
| Page web du séminaire / Seminar's webpage |