Lepton Acceleration in the Vicinity of the Event Horizon: Very High Energy Emissions from Supermassive Black Holes

Kouichi Hirotani, Hung Yi Pu, Lupin Chun Che Lin, Albert K.H. Kong, Satoki Matsushita, Keiichi Asada, Hsiang Kuang Chang, Pak Hin T. Tam

研究成果: 雜誌貢獻期刊論文同行評審

16 引文 斯高帕斯(Scopus)


Around a rapidly rotating black hole (BH), when the plasma accretion rate is much less than the Eddington rate, the radiatively inefficient accretion flow (RIAF) cannot supply enough MeV photons that are capable of materializing as pairs. In such a charge-starved BH magnetosphere, the force-free condition breaks down in the polar funnels. Applying the pulsar outer-magnetospheric lepton accelerator theory to supermassive BHs, we demonstrate that a strong electric field arises along the magnetic field lines in the direct vicinity of the event horizon in the funnels, that the electrons and positrons are accelerated up to 100 TeV in this vacuum gap, and that these leptons emit copious photons via inverse-Compton (IC) processes between 0.1 and 30 TeV for a distant observer. It is found that these IC fluxes will be detectable with Imaging Atmospheric Cherenkov Telescopes, provided that a low-luminosity active galactic nucleus is located within 1 Mpc for a million-solar-mass central BH or within 30 Mpc for a billion-solar-mass central BH. These very high energy fluxes are beamed in a relatively small solid angle around the rotation axis because of the inhomogeneous and anisotropic distribution of the RIAF photon field and show an anticorrelation with the RIAF submillimeter fluxes. The gap luminosity depends little on the 3D magnetic field configuration, because the Goldreich-Julian charge density, and hence the exerted electric field, is essentially governed by the frame-dragging effect, not by the magnetic field configuration.

期刊Astrophysical Journal
出版狀態已發佈 - 2017 8月 10

ASJC Scopus subject areas

  • 天文和天體物理學
  • 空間與行星科學


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