Physics of Pair-producing Gaps in Black Hole Magnetospheres: Two-dimensional General Relativistic Particle-in-cell Simulations
Black holes can launch powerful jets through the Blandford–Znajek process. This relies on enough plasma in the jet funnel to conduct the necessary current. However, in some low-luminosity active galactic nuclei, the plasma supply near the jet base may be an issue. It has been proposed that spark gap...
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IOP Publishing
2025-01-01
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| Series: | The Astrophysical Journal |
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| Online Access: | https://doi.org/10.3847/1538-4357/adce79 |
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| author | Yajie Yuan Alexander Y. Chen Martin Luepker |
| author_facet | Yajie Yuan Alexander Y. Chen Martin Luepker |
| author_sort | Yajie Yuan |
| collection | DOAJ |
| description | Black holes can launch powerful jets through the Blandford–Znajek process. This relies on enough plasma in the jet funnel to conduct the necessary current. However, in some low-luminosity active galactic nuclei, the plasma supply near the jet base may be an issue. It has been proposed that spark gaps—local regions with unscreened electric field—can form in the magnetosphere, accelerating particles to initiate pair cascades, thus filling the jet funnel with plasma. In this paper, we carry out 2D general relativistic particle-in-cell (GRPIC) simulations of the gap, including self-consistent treatment of inverse Compton scattering and pair production. We observe gap dynamics that is fully consistent with our earlier 1D GRPIC simulations. We find strong dependence of the gap power on the soft photon spectrum and energy density, as well as the strength of the horizon magnetic field. We derive physically motivated scaling relations, and applying to M87, we find that the gap may be energetically viable for the observed TeV flares. For Sgr A*, the energy dissipated in the gap may also be sufficient to power the X-ray flares. |
| format | Article |
| id | doaj-art-be2a51cd673f4f96b5282ae19e1a54aa |
| institution | OA Journals |
| issn | 1538-4357 |
| language | English |
| publishDate | 2025-01-01 |
| publisher | IOP Publishing |
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| series | The Astrophysical Journal |
| spelling | doaj-art-be2a51cd673f4f96b5282ae19e1a54aa2025-08-20T01:52:38ZengIOP PublishingThe Astrophysical Journal1538-43572025-01-01985215910.3847/1538-4357/adce79Physics of Pair-producing Gaps in Black Hole Magnetospheres: Two-dimensional General Relativistic Particle-in-cell SimulationsYajie Yuan0https://orcid.org/0000-0002-0108-4774Alexander Y. Chen1https://orcid.org/0000-0002-4738-1168Martin Luepker2https://orcid.org/0009-0004-3333-7897Physics Department and McDonnell Center for the Space Sciences, Washington University in St. Louis , St. Louis, MO 63130, USA ; yajiey@wustl.eduPhysics Department and McDonnell Center for the Space Sciences, Washington University in St. Louis , St. Louis, MO 63130, USA ; yajiey@wustl.eduPhysics Department and McDonnell Center for the Space Sciences, Washington University in St. Louis , St. Louis, MO 63130, USA ; yajiey@wustl.eduBlack holes can launch powerful jets through the Blandford–Znajek process. This relies on enough plasma in the jet funnel to conduct the necessary current. However, in some low-luminosity active galactic nuclei, the plasma supply near the jet base may be an issue. It has been proposed that spark gaps—local regions with unscreened electric field—can form in the magnetosphere, accelerating particles to initiate pair cascades, thus filling the jet funnel with plasma. In this paper, we carry out 2D general relativistic particle-in-cell (GRPIC) simulations of the gap, including self-consistent treatment of inverse Compton scattering and pair production. We observe gap dynamics that is fully consistent with our earlier 1D GRPIC simulations. We find strong dependence of the gap power on the soft photon spectrum and energy density, as well as the strength of the horizon magnetic field. We derive physically motivated scaling relations, and applying to M87, we find that the gap may be energetically viable for the observed TeV flares. For Sgr A*, the energy dissipated in the gap may also be sufficient to power the X-ray flares.https://doi.org/10.3847/1538-4357/adce79Black hole physicsHigh energy astrophysicsPlasma astrophysicsNon-thermal radiation sources |
| spellingShingle | Yajie Yuan Alexander Y. Chen Martin Luepker Physics of Pair-producing Gaps in Black Hole Magnetospheres: Two-dimensional General Relativistic Particle-in-cell Simulations The Astrophysical Journal Black hole physics High energy astrophysics Plasma astrophysics Non-thermal radiation sources |
| title | Physics of Pair-producing Gaps in Black Hole Magnetospheres: Two-dimensional General Relativistic Particle-in-cell Simulations |
| title_full | Physics of Pair-producing Gaps in Black Hole Magnetospheres: Two-dimensional General Relativistic Particle-in-cell Simulations |
| title_fullStr | Physics of Pair-producing Gaps in Black Hole Magnetospheres: Two-dimensional General Relativistic Particle-in-cell Simulations |
| title_full_unstemmed | Physics of Pair-producing Gaps in Black Hole Magnetospheres: Two-dimensional General Relativistic Particle-in-cell Simulations |
| title_short | Physics of Pair-producing Gaps in Black Hole Magnetospheres: Two-dimensional General Relativistic Particle-in-cell Simulations |
| title_sort | physics of pair producing gaps in black hole magnetospheres two dimensional general relativistic particle in cell simulations |
| topic | Black hole physics High energy astrophysics Plasma astrophysics Non-thermal radiation sources |
| url | https://doi.org/10.3847/1538-4357/adce79 |
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