General Relativistic Radiation Magnetohydrodynamics Simulations of Precessing Tilted Super-Eddington Disks

TL;DR

This study uses 3D general relativistic radiation magnetohydrodynamics simulations to explore precessing tilted super-Eddington disks around spinning black holes, revealing precession-induced variability in outflows and luminosity.

Contribution

It presents the first detailed simulation of tilted super-Eddington disks showing precession and its effects on outflows and luminosity variability.

Findings

Disk precession causes time-varying outflow directions.

Precession timescale matches observed QPO frequencies.

Outflows are mainly ejected along the outer disk's rotation axis.

Abstract

We perform a three-dimensional general relativistic radiation magnetohydrodynamics simulation of a tilted super-Eddington accretion disk around the spinning black hole (BH). The disk, that tilts and twists as it approaches the BH, precesses while maintaining its shape. The gas is mainly ejected around the rotation axis of the outer part of the disk rather than around the spin axis of the BH. The disk precession changes the ejection direction of the gas with time. The radiation energy is also released in approximately the same direction as the outflow, so the precession is expected to cause a quasi-periodic time-variation of the observed luminosity. The timescale of the precession is about $10$ s for the 10 solar mass BH and for the radial extent of the disk of several tens of gravitational radii. This timescale is consistent with the frequency of the low-frequency quasi-periodic oscillation ($0.01-1$ Hz) observed in some ultraluminous X-ray sources.