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

Abstract

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.more » 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.« less

Authors:
; ; ; ;  [1]; ;  [2];  [3]
  1. Academia Sinica, Institute of Astronomy and Astrophysics (ASIAA), P.O. Box 23-141, Taipei, Taiwan 10617, R.O.C. (China)
  2. Institute of Astronomy, Department of Physics, National Tsing Hua University, No. 101, Section 2, Kuang-Fu Road, Hsinchu, Taiwan 30013, R.O.C. (China)
  3. School of Physics and Astronomy, Sun Yat-Sen University, Zhuhai 519082 (China)
Publication Date:
OSTI Identifier:
22663250
Resource Type:
Journal Article
Resource Relation:
Journal Name: Astrophysical Journal; Journal Volume: 845; Journal Issue: 1; Other Information: Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; ANISOTROPY; BLACK HOLES; DISTRIBUTION; ELECTRIC FIELDS; ELECTRONS; EMISSION; GALAXY NUCLEI; GAMMA RADIATION; LUMINOSITY; MAGNETIC FIELD CONFIGURATIONS; MAGNETIC FIELDS; MASS; MEV RANGE; PHOTONS; PLASMA; POSITRONS; PULSARS; ROTATION; STARS; TEV RANGE

Citation Formats

Hirotani, Kouichi, Pu, Hung-Yi, Lin, Lupin Chun-Che, Matsushita, Satoki, Asada, Keiichi, Kong, Albert K. H, Chang, Hsiang-Kuang, and Tam, Pak-Hin T., E-mail: hirotani@tiara.sinica.edu.tw. Lepton Acceleration in the Vicinity of the Event Horizon: Very High Energy Emissions from Supermassive Black Holes. United States: N. p., 2017. Web. doi:10.3847/1538-4357/AA7895.
Hirotani, Kouichi, Pu, Hung-Yi, Lin, Lupin Chun-Che, Matsushita, Satoki, Asada, Keiichi, Kong, Albert K. H, Chang, Hsiang-Kuang, & Tam, Pak-Hin T., E-mail: hirotani@tiara.sinica.edu.tw. Lepton Acceleration in the Vicinity of the Event Horizon: Very High Energy Emissions from Supermassive Black Holes. United States. doi:10.3847/1538-4357/AA7895.
Hirotani, Kouichi, Pu, Hung-Yi, Lin, Lupin Chun-Che, Matsushita, Satoki, Asada, Keiichi, Kong, Albert K. H, Chang, Hsiang-Kuang, and Tam, Pak-Hin T., E-mail: hirotani@tiara.sinica.edu.tw. Thu . "Lepton Acceleration in the Vicinity of the Event Horizon: Very High Energy Emissions from Supermassive Black Holes". United States. doi:10.3847/1538-4357/AA7895.
@article{osti_22663250,
title = {Lepton Acceleration in the Vicinity of the Event Horizon: Very High Energy Emissions from Supermassive Black Holes},
author = {Hirotani, Kouichi and Pu, Hung-Yi and Lin, Lupin Chun-Che and Matsushita, Satoki and Asada, Keiichi and Kong, Albert K. H and Chang, Hsiang-Kuang and Tam, Pak-Hin T., E-mail: hirotani@tiara.sinica.edu.tw},
abstractNote = {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.},
doi = {10.3847/1538-4357/AA7895},
journal = {Astrophysical Journal},
number = 1,
volume = 845,
place = {United States},
year = {Thu Aug 10 00:00:00 EDT 2017},
month = {Thu Aug 10 00:00:00 EDT 2017}
}