The velocity anisotropy of galaxy clusters & their assembly history

We characterize galaxy orbits in nine massive clusters (0.19<z<0.45) from the CLASH-VLT survey by determining their velocity anisotropy profiles, β(r). Leveraging an unprecedented number of spectroscopic members (150 to 950 per cluster), we reveal significant differences in orbital distributions across clusters and investigate the causes of this variance. By comparing our results with z 0 clusters and two sets of cosmological numerical simulations, we show that β(r) carries key information on a cluster’s assembly history. Finally, we use clusters from the DESI survey to test theoretical predictions regarding the β-dependence of cluster assembly bias in the large-scale structure.

Dr. Andrea Biviano, Osservatorio Astronomico di Trieste (OATs, INAF)

Andrea Biviano earned his PhD in Astrophysics from the University of Trieste in 1992. Following five years of postdoctoral research in Paris, Leiden, and Madrid, he joined the Trieste Astronomical Observatory (INAF), where he is currently Research Director. His primary research focuses on the internal structure and dynamics of galaxy clusters and the evolution of cluster galaxies. He is also a recognized Builder of the Euclid Consortium.