A Study of the Accretion State of Magnetically Arrested Disks across Black Hole Spins for Radiatively Inefficient Accretion Flows

Abstract

The study of magnetically arrested disks (MAD) has attracted strong interest in recent years because these disk configurations were found to generate strong jets, as observed in many accreting systems. Here, we present the results of 14 general relativistic magnetohydrodynamic simulations of advection-dominated accretion flow in the MAD state across black hole (BH) spins, carried out with cuHARM. Our main findings are as follows. (i) The jets transport a significant amount of angular momentum to infinity in the form of Maxwell stresses. For positive, high spin, the rate of angular momentum transport is about five times higher than for negative spin. This contribution is nearly absent for a nonrotating BH. (ii) The mass accretion rate and the MAD parameter, both calculated at the horizon, are not correlated. However, their time derivatives are anticorrelated for every spin. (iii) For zero spin, the contribution of the toroidal component of the magnetic field to the magnetic pressure is negligible, while for a fast-spinning BH, it is on the same order as the contribution of the radial magnetic component. For high positive spin, the toroidal component even dominates. (iv) For negative spins, the jets are narrower than their positive-spin counterparts, while their fluctuations are stronger. The weak jet from the nonrotating BH is the widest with the weakest fluctuations. Our results highlight the complex nonlinear connection between the black hole spin and the resulting disk and jet properties in the MAD regime.