Lecturer: Dr. Matteo Tomassetti Affiliation: Racah Institute of Physics, The Hebrew University of Jerusalem Abstract: In this talk I will show results on the analysis of the VELA suite of zoom-in cosmological simulations. Previous studies have shown that a significant fraction of high-redshift galaxies evolve from a diffuse phase into a compaction phase followed by a quenching event. Part of my research work focuses on determining the shape of the dark matter component as well as the stellar and gaseous disk during these three phases. In the first part of the talk I will show different methods to determine the shape of the different components and discuss their accuracy. Next, I will study the connection between compaction and roundness. In particular, I will show that soon after the halo assembly, because the halo forms inside a dominant filament, it has an elongated prolate ellipsoid-like shape. The stellar system follows the configuration of the dark-matter and is also elongated as long as the core is DM-dominated. After compaction, once the system has become self-gravitating, both the dark-matter and stellar component tend to become rounder. Lastly, I will also talk about the relative orientations between the different components and discuss their stability. Additional details of the upcoming Astrophysics' seminars can be found on the following link. ‏האירוע הזה כולל שיחת וידאו ב-Google Hangouts. הצטרף: https://hangouts.google.com/hangouts/_/mail.huji.ac.il/astrophysics?hceid=bWFpbC5odWppLmFjLmlsX2c0czhydDlpcmhwZzRvdGNybWIzZGFqcjdvQGdyb3VwLmNhbGVuZGFyLmdvb2dsZS5jb20.77n6clmp9l3etvkqrlr162d7qs&hs=121