Gap-type Particle Acceleration in the Magnetospheres of Rotating Supermassive Black Holes

Abstract

The detection of rapidly variable gamma-ray emission in active galactic nuclei has generated renewed interest in magnetospheric particle acceleration and emission scenarios. In order to explore its potential, we study the possibility of steady gap acceleration around the null surface of a rotating black hole magnetosphere. We employ a simplified (1D) description along with the general relativistic expression of Gauss's law, and we assume that the gap is embedded in the radiation field of a radiatively inefficient accretion flow. The model is used to derive expressions for the radial distribution of the parallel electric field component, the electron and positron charge density, the particle Lorentz factor, and the number density of $\gamma$-ray photons. We integrate the set of equations numerically, imposing suitable boundary conditions. The results show that the existence of a steady gap solution for a relative high value of the global current is in principle possible if charge injection of both species is allowed at the boundaries. We present gap solutions for different choices of the global current and the accretion rate. When put in context, our results suggest that the variable very high energy $\gamma$-ray emission in M87 could be compatible with a magnetospheric origin.

20 pages, 11 figures; ApJ accepted; minor typos fixed to match published version

References in corpus (11)

• First M87 Event Horizon Telescope Results. I. The Shadow of the Supermassive Black Hole
• First M87 Event Horizon Telescope Results. VI. The Shadow and Mass of the Central Black Hole
• First M87 Event Horizon Telescope Results. V. Physical Origin of the Asymmetric Ring
• Radiatively Inefficient Accretion in Nearby Galaxies
• Black hole lightning due to particle acceleration at subhorizon scales
• Production of TeV gamma-radiation in the vicinity of the supermassive black hole in the giant radiogalaxy M87
• Variable TeV emission as a manifestation of jet formation in M87?
• Existence of steady gap solutions in rotating black hole magnetospheres
• Lepton acceleration in the vicinity of the event horizon: High-energy and Very-high-energy emissions from rotating black holes with various masses
• Magnetospheric Gamma-Ray Emission in Active Galactic Nuclei
• Lepton acceleration in the vicinity of the event horizon: Very-high-energy emissions from super-massive black holes

Cited by in corpus (8)

• Broadband Multi-wavelength Properties of M87 during the 2018 EHT Campaign including a Very High Energy Flaring Episode
• Active Galactic Nuclei as potential Sources of Ultra-High Energy Cosmic Rays
• Radiation GRMHD simulations of M87: funnel properties and prospects for gap acceleration
• Blazars at Very High Energies: Emission Modelling
• Implications from the velocity profile of the M87 jet: a possibility of a slowly rotating black hole magnetosphere
• Electron-beam interaction with emission-line clouds in blazars
• Two-dimensional Particle-in-Cell simulations of axisymmetric black hole magnetospheres: angular dependence of the Blandford-Znajek flux
• Constraining cosmic-ray acceleration in the magnetospheric gaps of Sgr A*