Séminaire/Seminar Galaxies |
| « Beyond AGN Feedback: the role of environment and assembly history in shaping X-ray properties of galaxy groups and clusters » |
|
Ilaria Marini |
| Why is the population of galaxy groups and clusters so diverse? Why do many systems deviate significantly from the expected ????–mass relation? What drives their systematically low hot gas mass fractions? Is AGN feedback solely responsible, or is the picture more complex—potentially influenced not only by when energy is injected into the intra-group and intra-cluster medium, but also where this energy is deposited within the evolving cosmic web? To explore these fundamental questions, we use the Magneticum hydrodynamical simulation to trace the assembly and thermal evolution of halos that evolve into the present-day population of galaxy groups and clusters, down to redshift ??<2. We analyze the hot gas content and X-ray detectability of both group- and cluster-sized halos, and demonstrate that environment—specifically a halo’s position within the cosmic web and its assembly history—plays a pivotal role in shaping their observable properties. Our results show that systems forming in denser regions, or experiencing late, rapid mass accretion, are more likely to retain hot gas and exhibit higher X-ray luminosities. In contrast, early-forming, isolated systems often remain X-ray faint, despite having comparable total halo masses. AGN feedback alone cannot fully account for this diversity; instead, we reveal a complex interplay between feedback and environment—an emergent dependence on large-scale structure that both mimics and amplifies assembly bias. |
|
jeudi 22 mai 2025 - 11:30 Salle Planck Institut d'Astrophysique de Paris |
| Page web du séminaire / Seminar's webpage |