Seminar

Drastic Times, Drastic Measures: Interpreting Rotation Measures in the Galactic Center Using Multi-Scale 3D MHD Simulations of Stellar Wind Accretion

Sagittarius A* (Sgr A*), the supermassive black hole at the center of the Milky Way, provides a unique laboratory for studying low-luminosity active galactic nuclei across a range of dynamical scales due to its proximity and the corresponding wealth of observational data. Here I present 3D MHD simulations that track accretion from the winds of the 30 Wolf-Rayet stars orbiting at ~ parsec scales all the way down to a few hundred Schwarzschild radii of the central black hole. The main focus of my talk will be the result that, in the same simulation, we are able to reproduce the large rotation measures of the galactic center magnetar and Sgr A* as well as the total diffuse X-ray luminosity observed by Chandra. I will discuss the plausibility of this scenario and make predictions about 1) future detections of galactic center pulsars and 2) the time variability of the rotation measure of Sgr A* going forward. Finally, I will present preliminary results on the flow structure at the innermost radii of the simulation and their implications for the horizon-scale, general relativistic magneto-hydrodynamic (GRMHD) simulations that are often used to interpret the multi-frequency emission of Sgr A*.

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