Changing-look (CL) phenomenon can be generally confirmed by the emergence or disappearance of Broad Emission Line, which challenge the understanding of AGN unification paradigm and accretion disk model. Dark Energy Spectroscopic Instrument (DESI) provides a unique opportunity to systematical study CL-AGNs, which enable us to investigate it by cross-matching the spectra of DESI early data and SDSS DR16. We discovered about hundreds of CL-AGNs and candidates, including both low- ionization and high-ionization Broad Emission Line. We also found that the timescale for these different lines is quite different, which may indicate a CL sequence during continuum luminosity continuous variation.
BIO
Weijian Guo received his Ph.D. in Astronomy from NAOC in 2022, after which he became a post-doc fellow in the NAOC all-sky survey and the Thirty Meter Telescope team. He is also a member in Dark Energy Spectroscopic Instrument. His research focuses on the AGN related topics such as accretion disk, broad line region and reverberation mapping etc.
