The Relativistic Outflow Driven by the Large-scale Magnetic Field from an Accretion Disk

Outflows/jets are ubiquitous in a wide range of astrophysical objects, yet the mechanisms responsible for their generation remain elusive. One hypothesis is that they are magnetically driven. Based on general relativistic MHD equations, we establish a formulation to describe the outflows driven by l...

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Main Authors: Wei Xie, Wei-Hua Lei
Format: Article
Language:English
Published: IOP Publishing 2025-01-01
Series:The Astrophysical Journal
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Online Access:https://doi.org/10.3847/1538-4357/adc100
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author Wei Xie
Wei-Hua Lei
author_facet Wei Xie
Wei-Hua Lei
author_sort Wei Xie
collection DOAJ
description Outflows/jets are ubiquitous in a wide range of astrophysical objects, yet the mechanisms responsible for their generation remain elusive. One hypothesis is that they are magnetically driven. Based on general relativistic MHD equations, we establish a formulation to describe the outflows driven by large-scale magnetic fields from the accretion disk in Schwarzschild spacetime. The outflow solution manifests as a contour level of a “Bernoulli” function, which is determined by ensuring that it passes through both the slow and fast magnetosonic points. This approach is a general relativistic extension to the classical treatment of X. Cao & H. C. Spruit. The initial plasma β that permits magnetically driven outflow solutions is constrained, with the slow magnetosonic point above the footpoint setting an upper limit ( β _b  ≲ 2) and the Alfvén point inside the light cylinder setting a lower limit ( β _b  ≳ 0.02). The higher the magnetization, the higher the temperature allowed, leading to relativistic outflows/jets. We investigate the relativistic outflows/jets of several typical objects, such as active galactic nuclei, X-ray binaries, and gamma-ray bursts. The results indicate that all of these phenomena require strongly magnetized, high-temperature outflows as initial conditions, suggesting a potential association between the production of relativistic outflows/jets and corona-like structures.
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spelling doaj-art-ca18ad60cb3343299bafc035bc4fcb022025-08-20T03:18:49ZengIOP PublishingThe Astrophysical Journal1538-43572025-01-01983214610.3847/1538-4357/adc100The Relativistic Outflow Driven by the Large-scale Magnetic Field from an Accretion DiskWei Xie0https://orcid.org/0000-0001-5553-4577Wei-Hua Lei1https://orcid.org/0000-0003-3440-1526Department of Astronomy, School of Physics and Electronic Science, Guizhou Normal University , Guiyang 550025, People’s Republic of China ; xieweispring@gznu.edu.cn; Guizhou Provincial Key Laboratory of Radio Astronomy and Data Processing, Guizhou Normal University , Guiyang 550025, People’s Republic of ChinaDepartment of Astronomy, School of Physics, Huazhong University of Science and Technology , Wuhan 430074, People’s Republic of China ; leiwh@hust.edu.cnOutflows/jets are ubiquitous in a wide range of astrophysical objects, yet the mechanisms responsible for their generation remain elusive. One hypothesis is that they are magnetically driven. Based on general relativistic MHD equations, we establish a formulation to describe the outflows driven by large-scale magnetic fields from the accretion disk in Schwarzschild spacetime. The outflow solution manifests as a contour level of a “Bernoulli” function, which is determined by ensuring that it passes through both the slow and fast magnetosonic points. This approach is a general relativistic extension to the classical treatment of X. Cao & H. C. Spruit. The initial plasma β that permits magnetically driven outflow solutions is constrained, with the slow magnetosonic point above the footpoint setting an upper limit ( β _b  ≲ 2) and the Alfvén point inside the light cylinder setting a lower limit ( β _b  ≳ 0.02). The higher the magnetization, the higher the temperature allowed, leading to relativistic outflows/jets. We investigate the relativistic outflows/jets of several typical objects, such as active galactic nuclei, X-ray binaries, and gamma-ray bursts. The results indicate that all of these phenomena require strongly magnetized, high-temperature outflows as initial conditions, suggesting a potential association between the production of relativistic outflows/jets and corona-like structures.https://doi.org/10.3847/1538-4357/adc100Black holesHigh energy astrophysicsAstrophysical fluid dynamicsMagnetohydrodynamicsRelativistic jets
spellingShingle Wei Xie
Wei-Hua Lei
The Relativistic Outflow Driven by the Large-scale Magnetic Field from an Accretion Disk
The Astrophysical Journal
Black holes
High energy astrophysics
Astrophysical fluid dynamics
Magnetohydrodynamics
Relativistic jets
title The Relativistic Outflow Driven by the Large-scale Magnetic Field from an Accretion Disk
title_full The Relativistic Outflow Driven by the Large-scale Magnetic Field from an Accretion Disk
title_fullStr The Relativistic Outflow Driven by the Large-scale Magnetic Field from an Accretion Disk
title_full_unstemmed The Relativistic Outflow Driven by the Large-scale Magnetic Field from an Accretion Disk
title_short The Relativistic Outflow Driven by the Large-scale Magnetic Field from an Accretion Disk
title_sort relativistic outflow driven by the large scale magnetic field from an accretion disk
topic Black holes
High energy astrophysics
Astrophysical fluid dynamics
Magnetohydrodynamics
Relativistic jets
url https://doi.org/10.3847/1538-4357/adc100
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