Annu. Rev. Astron. Astrophys. 1988. 36: 539-598
Copyright © 1998 by . All rights reserved

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MODELING EXTRAGALACTIC JETS

Attilio Ferrari


Dipartimento Fisica Generale, Università di Torino, Via Giuria 1, Torino, I-10125

Osservatorio Astronomico di Torino, Pino Torinese, I-10025 Italy; e-mail: ferrari@to.astro.it


Abstract. Extragalactic jets were discovered and initially studied by radio astronomers in connection with extended radio sources. At present, the combination of jets and disks is considered the crucial element in unification models for all active galactic nuclei (AGNs). The acceleration and propagation conditions of jets, together with the aspect ratio of the disk/jet geometry with respect to the observer, shape the morphologies of AGNs. However, these phenomenological models are very complex from the physical and mathematical point of view, as they involve different elements of the theories of gravitation, fluid dynamics, and electrodynamics in a highly nonlinear combination and in conditions not easily reproducible in laboratory plasma or fluid experiments. In the last ten years, theorists have attacked the subject with advanced analytical and numerical methods, and some important results have already been established that confirm the global scenario, although we are still far from a complete physical interpretation. This review summarizes the main results on the art of jet modeling, emphasizing the limitations of the available models and the possibility of new developments.


Table of Contents

HISTORICAL INTRODUCTION

THE PHENOMENOLOGICAL MODEL
Phenomenology of an Extended Radio Source
Jets and Unified Models for Active Galactic Nuclei

ORIGIN OF JETS: THE BLACK HOLE CONNECTION
Collimated Outflows from Accretion Disks
Electromagnetic Winds from Black Hole/Disk Magnetospheres
Nonlinear Ejection Models
Observable Quantities

JET CONFINEMENT: THE INTERACTION WITH THE AMBIENT MEDIUM
Global Dynamics of Confined Jets
Global Electrodynamics of Confined Jets
Jet Instabilities
Nonlinear Evolution of Jet Dynamics
Astrophysical Applications and Comments

JET TERMINATION: THE COCOON
Hot Spots
Extended Lobes
Filaments
Numerical Models of Jet's Head Evolution
Understanding Jet Microphysics

RADIATION AND PARTICLE ACCELERATION IN LARGE-SCALE JETS
Evolution of the Relativistic Electron Distribution Function
Comments: Beaming Effects in Relativistic Outflows
Acceleration of Cosmic Rays in Extragalactic Radio Sources

OPEN PROBLEMS

REFERENCES

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