Accreting supermassive black holes (SMBHs) are known to show variable optical, ultraviolet and X-ray emission. One of the most intriguing aspects of this behaviour is associated with “changing- look’ sources, in which the optical/ultraviolet broad emission lines, produced by rapidly-moving material surrounding the SMBH, appear or disappear. In my talk I will discuss the drastic transformation of the X-ray properties of a nearby active galactic nucleus (AGN), following a changing-look event. After the optical/UV outburst the power-law component, produced in the X-ray corona, completely disappeared, and the spectrum instead became dominated by blackbody-like emission. This implies that the X-ray corona, ubiquitously found in AGN, was destroyed in the event. In my talk I will discuss in detail the results of our 450 days monitoring campaign on this source, and provide possible explanations for this phenomenon.

Location: Online (Zoom)

Meeting link: https://us02web.zoom.us/j/86149503748?pwd=TlpzazZlSG1kaFZzUlp6cDc5SnZHZz09 Meeting ID: 86149503748 Password: 7867