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Active galactic nuclei (AGN) are powered by accretion onto supermassive black holes (SMBHs) and play a central role in galaxy evolution by tracing SMBH growth across cosmic time. As some of the most luminous objects in the Universe, AGN provide unique laboratories for studying accretion physics and relativistic processes in extreme environments. However, the extremely small physical scales of the central engine make direct spatial resolution of AGN structures largely inaccessible. In this talk, I will present our recent efforts to probe AGN structure using X-ray observations, with particular emphasis on the circumnuclear torus and the X-ray–emitting corona. I will further discuss how these results inform our understanding of the co-evolution of SMBHs and their host galaxies from an X-ray perspective. Finally, I will introduce a novel approach to constraining SMBH spin and accretion disk properties, quantities that remain challenging to measure observationally.

BIO

Xiurui Zhao is a Postdoctoral Scholar at the California Institute of Technology. He received his Ph.D. from Clemson University in 2021, followed by postdoctoral appointments at the Center for Astrophysics | Harvard & Smithsonian (2021–2023) and the University of Illinois Urbana-Champaign (2023-2025). His research focuses on high-energy astrophysics, with an emphasis on the physics of supermassive black holes and active galactic nuclei. He also has broad interests in extragalactic surveys and time-domain astrophysics. More recently, he has developed an interest in linking the X-ray properties of stars to exoplanet habitability, preparing the source selection strategies for the next-generation telescopes such as Habitable Worlds Observatory.

Host: Wei Cui