Lunch talk on Sep. 4, 2023

Changing-look AGNs in the Dark Energy Spectroscopic Instrument (DESI)

Speaker: Weijian Guo (NAOC)

Venue: Video Conference

Time: 12:30 PM, Monday, Sep. 4, 2023

Abstract: 

The Changing-look (CL) phenomenon is often characterized by the appearance or disappearance of Broad Emission Lines (BELs) in AGNThis phenomenon challenges our understanding of the AGN unification paradigm and standard accretion disk model.  We utilize the DESI  to systematically search and study CL-AGNs with repeated spectra from the Sloan Digital Sky Survey Data Release 16. We have identified hundreds of CL-AGNs and candidates, including both low-ionization and high-ionization BELs. We found that that the timescales for the emergence or disappearance of different BELs vary significantly, which  suggests the existence of a CL sequence during the continuous variation of continuum luminosity.

Report PPT:  SWIFAR_Weijian Guo.pdf