Speaker
Description
We present a multiwavelength study of 798 Type 1 and 2607 Type 2 active galactic nuclei (AGN), combining optical spectroscopy with X-ray data from eROSITA and infrared observations from WISE. We investigate a scenario in which AGN accretion can weaken, disappear, and reform, driving structural changes across the nucleus with characteristic timescales. We find ~1000 low luminosity optically selected Type 2 AGN that are not detected in X-rays. Most of these non-detections cannot be explained by survey limits or obscuration, suggesting that their X-ray emission is intrinsically very weak or missing. A subset may represent a candidate true Type 2 AGN. We also show that standard WISE colour selection is biased toward luminous Type 2 AGN, missing many lower-luminosity systems. Our results support a disc–wind framework in which AGN classification depends not only on orientation, but also on luminosity-driven structural evolution.