English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools annual

Global: Zendy Free Plan

Global: Zendy Tools monthly

Global: Zendy Plus monthly

Around a rapidly rotating black hole (BH), when the plasma accretion rate ismuch less than the Eddington rate, the radiatively inefficient accretion flow(RIAF) cannot supply enough MeV photons that are capable of materializing aspairs. In such a charge-starved BH magnetosphere, the force-free conditionbreaks down in the polar funnels. Applying the pulsar outer-magnetosphericlepton accelerator theory to super-massive BHs, we demonstrate that a strongelectric field arises along the magnetic field lines in the direct vicinity ofthe event horizon in the funnels, that the electrons and positrons areaccelerated up to 100~TeV in this vacuum gap, and that these leptons emitcopious photons via inverse-Compton (IC) process between 0.1~TeV and 30~TeV fora distant observer. It is found that these IC fluxes will be detectable withImaging Atmospheric Cherenkov Telescopes, provided that a low-luminosity activegalactic nucleus is located within 1~Mpc for a million-solar-mass central BH orwithin 30~Mpc for a billion-solar-mass central BH. These very-high-energyfluxes are beamed in a relatively small solid angle around the rotation axisbecause of the inhomogeneous and anisotropic distribution of the RIAF photonfield, and show an anti-correlation with the RIAF submillimeter fluxes. The gapluminosity little depends on the three-dimensional magnetic-fieldconfiguration, because the Goldreich-Julian charge density, and hence theexerted electric field is essentially governed by the frame-dragging effect,not by the magnetic field configuration.

Lepton acceleration in the vicinity of the event horizon: Very-high-energy emissions from super-massive black holes