Title: Zoom in to the Final Parsec of Quasars with Variability

Speaker: 沈悦

Institute:  University of Illinois at Urbana-Champaign

Host: 武剑锋

Time: 2024.1.4 周四 10:00-12:00

Location: 物理楼 552

Abstract: 

The restless central engine of accreting supermassive black holes produces ubiquitous variability across broad ranges of wavelengths and timescales. Variability allows the study of the innermost structures around the SMBH that cannot be spatially resolved directly. In particular, reverberation mapping (RM) of the broad-line emission in response to light fluctuations from the accretion flow constrains the size, geometry and kinematics of the fast-moving gas around the SMBH, and provides a measurement of the central black hole mass. This RM technique (and its extension) is currently our primary method to measure black hole masses in distant quasars up to z>6. After a brief review on recent progress on AGN variability, I will discuss the current status of broad-line RM, and present results from decade-long monitoring programs and applications of RM results to galaxy-SMBH co-evolution. If there is time, I will end with a "twin quasar" puzzle that has been haunting us for the past few years.

Bio：

Dr. Yue Shen got his PhD from Princeton University in 2009. He went on to Harvard-Smithsonian Center for Astrophysics as a Clay postdoctoral fellow, and then to Carnegie Observatories as a Hubble postdoctoral fellow. He joined the astronomy faculty at the University of Illinois at Urbana-Champaign in 2015, and has been there since. Dr. Shen works in the broad field of extragalactic astronomy, and has made many original contributions to understanding the formation and evolution of supermassive black holes. His most recent interests include AGN reverberation mapping and the broad science enabled by synoptic sky surveys.