Disc tearing and Bardeen–Petterson alignment in GRMHD simulations of highly tilted thin accretion discs

Luminous active galactic nuclei (AGN) and X-Ray binaries (XRBs) often contain geometrically thin, radiatively cooled accretion discs. According to theory, these are -- in many cases initially highly misaligned with the black hole equator. In this work, we present first general relativistic magnetohydrodynamic simulations of very thin (h/r~0.015-0.05) discs around rapidly spinning (a~0.9) holes tilted by 45-65 degrees. We show that inner regions h/r<0.03 align equator, though out smaller radii than predicted analytic work. The aligned outer disc separated a sharp break tilt angle accompanied drop density. find frame-dragging overpowers viscosity, which is self-consistently produced magnetized turbulence, tearing apart forming precessing sub-disc surrounded slowly sub-disc. system produces pair jets for all initial values. At small distances launched precess together sub-disc, whereas at large they partially more slowly. If radius can be modeled accurately future emission model independent measurements spin based on precession-driven quasi-periodic oscillations may become possible.