"Imaging supermassive black holes: observations and theory"
Prof. Luciano Rezzolla
Institute for Theoretical Physics, Frankfurt (Germany)

Monday 15/9/2025 14:00-16:00 and Tuesday 16/9/2025 14:00-16:00

In the first lecture I will discuss how the first images of the supermassive black holes M87* and Sgr A* were obtained by the EHT collaboration exploiting the VLBI technique. I will also describe the theoretical aspects that have allowed us to model the dynamics of the plasma accreting onto the black hole and how the comparison between the theoretical images and the observations on a broad range of frequencies has allowed us to deduce the presence of supermassive black holes and to extract information about the accretion process. In the second lecture, I will discuss the differences in the analysis of the data from M87* and Sgr A*, and illustrate the lessons we have learned from these imaging process about strong-field gravity and alternatives to black holes and some recent ideas about light rings and ultra-compact objects.