Andrea Merloni - Extreme Variability from Supermassive Black Holes: highlights from eROSITA and other X-ray surveys

Friday 10 Oct 2025, 10:30 → 12:00 Europe/Berlin

I will report on the recent discoveries of peculiar (or exotic) transient and variable X-ray phenomena in the nuclei of nearby galaxies, with particular focus on 'Changing Look AGN', (full or partial) Tidal Disruption Events (TDE) and Quasi Periodic Eruptions (QPE). I will review their phenomenology, tentative population statistics, and discuss possible physical properties of these objects and their connections to GW emitters. In addition, I will discuss the role X-ray survey instruments play for the discovery and characterisation of strongly variable SMBH, focusing in particular on eROSITA (extended ROentgen Survey with an Imaging Telescope Array), the core instrument on the Russian-German Spektrum-Roentgen-Gamma (SRG) mission, which has completed 4 scans of the entire sky with unprecedented sensitivity in the 0.2-8 keV energy range.