The fate of nonradiative magnetized accretion flows: Magnetically frustrated convection

We present a scenario for nonradiative accretion onto the supermassive black hole at the Galactic center. Conducting MHD simulations with 1400(3) grid zones that break the axial and reflection symmetries of earlier investigations and extend inward from the Bondi radius, we find a quasi-hydrostatic radial density profile rho proportional to r(-0.72) with a superadiabatic gradient corresponding to an n similar to 0.72 polytrope. Buoyancy generated by magnetic dissipation is resisted by the same fields so effectively that energy is advected inward: a state of magnetically frustrated convection. This scenario is consistent with observational constraints on energetics and outer boundary conditions.