Abstract
Changing-look Active Galactic Nuclei（CLAGNs）are a rare class of AGNs whose broad emission lines appear or disappear within several months to years. Such a short time state change presents serious challenges to the well-known unification scheme of AGNs and the standard model of accretion disk around black hole. In this talk I will introduce our discoveries of about 100 CLAGNs, and several of them were even found to be repeating CLAGNs. I will describe the X-ray properties of some CLAGNs and show the evidences for the changing-obscuration triggered also by the evolution of accretion disks. The multiwavelength studies on CLAGNs in the future are needed in order to fully solve the puzzles of CLAGNs.
Anyone interested is welcome to attend.