Shanghai Astronomical Observatory Astrophysics Colloquium

Title：The Impact of External Feedback on the Formation of Galaxies and Clusters: Shaping the Cosmic Ecosystem

外部反馈对星系和星系团形成的影响：塑造宇宙生态系统

Speaker：Prof. Renyue Cen (Zhejiang University)

Special Time：2:00 PM May 15th (Friday)

Location:Lecture Hall, 3rd floor

Abstract：

Feedback processes from active galactic nuclei (AGN) that play a primary role in shaping the galactic ecosystem remain poorly understood. Observations are inconsistent with the canonical internal AGN‑driven feedback scenario. I propose a new external feedback paradigm, in which gas accretion onto galaxies located in filaments and protoclusters at the peak epoch of cosmic star formation (z = 2–3) is significantly reduced – poised to resolve the overcooling problem in galaxy formation. The ubiquitously observed FR II giant radio lobes can physically power this external feedback model by energizing about 10–20% of the intergalactic medium volume around filaments and protoclusters, precisely where most stars in galaxies form. I will present new results that directly probe FR II feedback strength at z > 1. Finally, I will highlight how the Square Kilometre Array (SKA) is set to be a transformative force in tackling long‑standing mysteries such as the entropy core problem in clusters, the cool‑core versus non‑cool‑core dichotomy, the galactic‑scale missing baryon problem, and the S₈ tension that challenges our cosmological model. Its unprecedented sensitivity and resolution across a wide range of radio frequencies will finally allow us to "see" and understand the hidden workings of the cosmic ecosystem.

CV：

Education

1981-1985   Fudan University, Physics, Bachelor of Science 

1986-1990   Princeton University, Astrophysics, PhD

Work Experience

1990-1992   Princeton University, Department of Astrophysical Sciences, Postdoc  

1992-1994   Princeton University Observatory, Researcher (rank of Assistant Professor)

1994-1999   Princeton University Observatory, Astronomer (rank of Associate Professor)

1999-2022   Princeton University Observatory, Senior Astronomer (rank of Professor)

2022.10-   Zhejiang University, School of Physics,  Chair Professor 

            Zhejiang   University, Institute for Advanced Study In Physics, Director, 

            Center for Cosmology and Computational Astrophysics （C3A）