主持人：刘纪认 研究员

时间：2026年11月16日（周一）14：30

地点：犀浦校区二教2539会议室

腾讯会议号：622 637 857

题目：Probing Black Hole Accretion with X-ray Time Delays

主讲人：Yu Wei

Wei Yu received his bachelor’s degree in physics from Jilin University in 2019 and his PhD in high-energy astrophysics from the Institute of High Energy Physics, Chinese Academy of Sciences, in 2024. He is currently a Humboldt Research Fellow at the Institute for Astronomy and Astrophysics, University of Tübingen, Germany. His research focuses on accretion physics in black hole and neutron star X-ray binaries, using X-ray spectroscopy, timing and polarimetry to probe accretion flow geometry. He is particularly interested in X-ray reverberation mapping in stellar-mass black holes and active galactic nuclei. His research also extends to machine learning applications in high-energy astrophysics.

Abstract:

Black holes in binary systems accrete gas from companion stars, producing rapidly varying X-rays. Although the inner accretion flow is too small to image directly, time delays between variations at different X-ray energies allow us to probe its structure. Some delays are thought to trace disturbances travelling through the inflowing gas, while others are X-ray “echoes” produced when the disc responds to radiation from a hot region known as the corona. In this talk, I will introduce these processes and explain how they help us study the geometry of the disc and corona. I will present recent Insight-HXMT and NICER results, including the first detection of an echo associated with the high-energy Compton reflection hump and the evolution of hard X-ray delays across different sources and accretion states. I will discuss how overlapping delay components affect the observed behaviour and what these measurements can tell us about the structure and evolution of accretion flows.