Guest
Arguably the most extensively studied (supermassive) black hole in our universe is Sgr A*, which is found at the center of our galaxy and a prime target of the Event Horizon Telescope (EHT): The culmination of decade-long quest to photograph the black hole shadow. Due to the availability of high resolution, high cadence observational data across the electromagnetic spectrum, it forms a critical benchmark for numerical simulations. One open mystery is the origin of daily/weekly flares observed in the NIR and X-Ray which originate very close to the black hole, and were not found in general relativistic magnetohydrodynamics (GRMHD) simulations. The absence of any self-consistent model or simulation producing these flares and/or hotspots illustrates that our understanding of the microphysics in accretion disks is incomplete. Several models have been proposed to address this discrepancy, including magnetic reconnection in current sheets due to the formation of plasmoids. Plasmoids are bubbles of hot, magnetized g
