Extreme AGNs and Transients: When Black Holes Misbehave

Session

Changing-look AGNs

6 Aug 2025, 09:30

The University of Hong Kong

13. New and Puzzling Types of Transient Phenomena from Accreting Supermassive Black Holes

Prof. Benny Trakhtenbrot (Tel Aviv University)

06/08/2025, 09:30

A growing number of transient phenomena in galaxy nuclei have recently begun to shed new light on SMBH demographics and the physics of gas accretion onto these objects, tracing events where this accretion has drastically intensified, diminished, and/or otherwise disturbed, over surprisingly short timescales. These phenomena include “changing look AGN” and other, poorly understood flares from...

14. Changing-State AGN and Rare AGN Transients

Prof. Claudio Ricci (University of Geneva)

06/08/2025, 10:30

AGN are known to show flux variability over all observable timescales and across the entire electromagnetic spectrum. Over the past decade, a growing number of sources have been observed to show dramatic flux and spectral changes, both in the X-rays and in the optical/UV. Such events, commonly described as “changing-look AGN”, can be divided into two well-defined classes. Changing-obscuration...

3. SMBH Transients and Broad-line Dynamics

Prof. Wu Qingwen

08/08/2025, 09:30

More and more transients are found in the nuclear region of galaxies, such as tidal disruption event, changing-look AGNs, ambiguous nuclear transient etc. It is possible to learn the physical evolution of accretion, jet and BLR based on a single SMBH object now even though the physical mechanism triggers these transients may be still unclear. I will introduce: the possible physical mechanism...