Hybrid Black Hole and Disk-Driven Jets: Steady Axisymmetric Ideal MHD Modeling

TL;DR

This paper develops a semi-analytical steady MHD model for hybrid black hole and disk-driven jets, revealing how magnetic field configurations influence jet launching, structure, and observable features like limb-brightening.

Contribution

It introduces a new hybrid jet model combining black hole and disk-driven components with a novel constraint on magnetic field configurations and flow solutions.

Findings

Discontinuities in field-line angular velocity cause velocity shear and density jumps.

Localized velocity and density enhancements may explain limb-brightening.

The model provides a framework for understanding jet launching sites and structures.

Abstract

Improved observational precision in relativistic jets has underscored the need for tractable theoretical models. In this study, we construct a semi-analytical hybrid jet model that incorporates both black hole-driven and disk-driven components within the framework of steady, axisymmetric, ideal MHD. We derive a condition that determines the launching sites of cold outflows, introducing a new constraint on the magnetic field configuration threading the accretion disk. Using the Bernoulli equation and critical point analysis, we derive flow solutions along various magnetic field lines. Our hybrid jet model shows that discontinuities in field-line angular velocity lead to clear velocity shear and density jumps at the interface between the two jet components. These features are accompanied by localized enhancements in velocity and density, potentially explaining the observed limb-brightening.