Abstract: The emission from accretion flows around the supermassive black holes M87* and Sgr A* originates from a relativistic plasma composed of ions, electrons, and possibly positrons. The characteristics of this extremely energetic plasma on microscopic scales fundamentally shape the system's large-scale dynamics. In this talk, I will describe the first-principles models of relativistic plasmas around black holes, necessary for interpreting and predicting the results of observations across the electromagnetic spectrum. Microscopic plasma effects not only affect the overall state of accretion but also alter the way we observe these systems by changing the distribution function of synchrotron-emitting electrons. Hot accretion flows, which are believed to operate around low-luminosity galactic nuclei, are often associated with strong outflows, winds, and jets. Nevertheless, the closest low-luminosity supermassive black hole, Sgr A*, located in the center of our galaxy, appears to lack a powerful jet. A simplified model of spherical accretion demonstrates why such systems might be unable to produce strong jets. Link to the Event Video |