Accretion state transition in active galactic nuclei: observational evidences

With an increasing number of empirical correlations between different classes of accreting systems, such as black hole X-ray binaries (XRBs), active galactic nuclei (AGNs) and recently tidal disruption events (TDEs), it was now believed that AGNs and XRBs have a similar central engine, namely the central black hole, the accretion flow and a relativistic jet, and most importantly a similar duty cycle. It was well understood that XRBs will experience state transition between different types of states, the reason is one can observe a full evolution cycle in XRGs with convenient time-scales (usually months). While a similar outburst in active galactic nuclei (AGNs) would last millions of years. Fortunately, different types of AGNs are supposed to be only at its own accretion stages, we can thus compare different types of AGNs as a whole with the evolution cycle of XRBs. In this talk, I will present our recent progresses in studying of super-Eddington accreting AGNs and its analogy to XRGs in super-Eddington states. Finally, I will briefly introduce our recent observation of a changing-look AGN and its possible explanation by using the state transition of AGNs. 

Xiaolong Yang (KIAA)
1st meeting room, KIAA
Fri, 2019-07-05 12:00 to 13:00