Invited Presentation

Very high energy emission from the direct vicinity of super-massive black holes

Author(s): Kouichi Hirotani (ASIAA)

Presenter: Kouichi Hirotani (ASIAA)

In a BH magnetosphere, when the plasma accretion rate is very low, the radiatively inefficient accretion flow (RIAF) cannot supply enough MeV photons that are necessary to screen an electric field along the magnetic field lines. In such a charge-starved region (or a gap), electrons and positrons are accelerated into ultra-relativistic energies, emitting copious gamma-rays via curvature and inverse-Compton processes. Some of such gamma-rays collide with the submillimeter photons emitted from the RIAF to materialize as pairs. The created pairs polarize to partially screen the original acceleration electric field. By solving such gap electrodynamics, we find that the central super-massive black holes of nearby low-luminosity active galactic nuclei emit 100GeV-10TeV photons at detectable level, and that their fluxes anti-correlate with the RIAF submillimeter fluxes. Thus, we can discriminate the gap emission from a jet emission, using e.g., ALMA and CTA.