Abstract:
The rich, dynamic phenomena of black hole accretion disks provide a unique laboratory for testing physics in the strong-gravity regime. In this seminar, I will present our recent work using 3D general relativistic magnetohydrodynamic (GRMHD) and radiative transfer (GRRT) simulations to connect the fundamental physics of magnetized accretion flows to their observable signatures. This work includes a new physical model for the flaring activity of Sagittarius A*, where our simulations show that large-scale magnetic reconnection events can power the observed flares and that frequency-dependent synchrotron self-absorption quantitatively reproduces characteristic multi-wavelength time delays. Shifting to a more fundamental investigation of tilted accretion disk dynamics, we have discovered a novel, magnetically-driven retrograde precession that directly counteracts the well-known Lense-Thirring effect from rotating BH, which has profound implications for the evolution of warped or misaligned disks. Building on these insights, my research extends to the grand challenge of binary black hole (BBH) accretion using a new GRMHD module I developed, whose preliminary results reveal unique QPO signatures from relativistic effects near the binary, providing crucial theoretical predictions for multi-messenger synergies between gravitational wave observatories like LISA and electromagnetic facilities like the ngEHT.
