Multimessenger Signatures of Tilted, Self-Gravitating, Black Hole Disks

TL;DR

This paper presents the first self-consistent relativistic simulations of tilted, self-gravitating black hole-disk systems, revealing how tilt influences gravitational wave emission, jet formation, and instability dynamics, highlighting their multimessenger potential.

Contribution

It introduces novel GRMHD simulations of tilted, self-gravitating black hole disks, exploring the impact of tilt on instabilities, jets, and gravitational wave signals.

Findings

Massive disks develop nonaxisymmetric instabilities influenced by tilt.

Magnetic stresses modulate instability growth and gravitational wave emission.

All models produce magnetically driven jets consistent with the BZ mechanism.

Abstract

We perform fully relativistic GRMHD simulations of magnetized, self-gravitating black hole-disk (BHD) systems in which the black hole spin is misaligned with the disk angular momentum. Massive disks (disk to BH mass ratios of $16-28\%$) around rapidly rotating black holes ($\chi\lesssim 0.97$) develop a nonaxisymmetric instability for tilt angles from $0^\circ$ to $180^\circ$. Magnetic stresses damp, but do not completely suppress, the nonaxisymmetric instability, and corresponding gravitational wave (GW) emission, in aligned systems, while they enhance it in antialigned BHDs: MRI-driven turbulence enhances angular momentum transport and accelerates nonlinear instability evolution in misaligned configurations. All models launch magnetically driven jets consistent with the Blandford-Znajek (BZ) mechanism, with collimation depending on spin orientation. The GWs reflect strong nonaxisymmetric structure from a persistent $m=1$ mode. The coupling between fast MRI and the slower nonaxisymmetric instability growth governs the outcome, with tilt controlling how MRI modifies the global mode. These simulations provide the first self-consistent GRMHD treatment of tilted, self-gravitating BHD systems and support their role as multimessenger sources.