Formation of Relativistic Outflows in Shearing Black Hole Accretion Coronae

Abstract

We examine the possibility that the relativistic jets observed in many active galactic nuclei may be powered by the Fermi acceleration of protons in a tenuous corona above a two-temperature accretion disk. In this picture the acceleration arises as a consequence of the shearing motion of the magnetic field in the corona, which is anchored in the underlying Keplerian disk. The protons in the corona have a power-law distribution because the density there is too low for proton-proton collisions to thermalize the energy supplied via Fermi acceleration. The same shear acceleration mechanism also operates in the disk itself, however, there the density is high enough for thermalization to occur and consequently the disk protons have a Maxwellian distribution. Particle acceleration in the corona leads to the development of a pressure-driven wind that passes through a critical point and subsequently transforms into a relativistic jet at large distances from the black hole. We combine the critical conditions for the wind with the structure equations for the disk and the corona to obtain a coupled disk/corona/wind model. Using the coupled model we compute the asymptotic Lorentz factor ${\Gamma }_{\infty }$ of the jet as a function of the cylindrical starting radius at the base of the outflow, in the corona. Our results suggest that $Γ_\infty \lapprox 10$, which is consistent with observations of superluminal motion in blazars. We show that collisions between the jet and broad-line emission clouds can produce high-energy radiation with a luminosity sufficient to power the $\gamma$-rays observed from blazars. Subject headings: radiation mechanisms: non-thermal, accretion, accretion disks, acceleration of particles, gamma rays: theory

50 pages, 13 figures, accepted by ApJ, 1999

References in corpus (2)

• Instability of toroidal magnetic field in jets and plerions
• Multiwavelength Observations of a Dramatic High Energy Flare in the Blazar 3C 279

Cited by in corpus (23)

• General Relativistic Magnetohydrodynamic Simulations of Jet Formation and Large-Scale Propagation from Black Hole Accretion Systems
• Shear acceleration in relativistic astrophysical jets
• Time-Dependent Stochastic Particle Acceleration in Astrophysical Plasmas: Exact Solutions Including Momentum-Dependent Escape
• Ultrahigh-energy Cosmic-ray Nuclei from Black Hole Jets: Recycling Galactic Cosmic Rays through Shear Acceleration
• Acceleration and Escape Processes of High-energy Particles in Turbulence inside Hot Accretion Flows
• Stochastic Particle Acceleration in Turbulence Generated by the Magnetorotational Instability
• Particle acceleration in rotating and shearing jets from AGN
• Particle Acceleration and the Production of Relativistic Outflows in Advection-Dominated Accretion Disks with Shocks
• Inner Boundary Conditions for Advection-Dominated Accretion onto Black Holes
• Effects of High-Energy Particles on Accretion Flows onto a Supermassive Black Hole
• Are the hotspots of radio galaxies the sites of in-situ acceleration of relativistic particles?
• Mass Outflows from Dissipative Shocks in Hot Accretion Flows
• TeV blazar variability: the firehose instability?
• Relativistic Outflows from Advection-Dominated Accretion Disks around Black Holes
• Noise storm continua: power estimates for electron acceleration
• Energetics of small electron acceleration episodes in the solar corona from radio noise storm observations
• Particle Acceleration in Advection-Dominated Accretion Disks with Shocks: Green's Function Energy Distribution
• Episodic Jets from Black Hole Accretion Disks
• The Effect of Non-Thermal Protons on the High Energy Spectra of Black Hole Binaries
• Self-consistent computation of gamma-ray spectra due to proton-proton interactions in black hole systems
• Electron acceleration in a post-flare decimetric continuum source
• Further constraints on electron acceleration in solar noise storms
• Inner region accretion flows onto black holes