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: | , |
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| Format: | Article |
| Language: | English |
| Published: |
IOP Publishing
2025-01-01
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| Series: | The Astrophysical Journal |
| Subjects: | |
| Online Access: | https://doi.org/10.3847/1538-4357/adc100 |
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| Summary: | 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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| ISSN: | 1538-4357 |