astro-ph/0103020

COSMIC RADIO JETS

Paul J. Wiita


Department of Astrophysical Sciences, Princeton University,
Princeton NJ 08544-1001, USA; on leave from the
Department of Physics and Astronomy, Georgia State University
E-mail: wiita@chara.gsu.edu

Abstract. Extragalactic radio sources, including quasars, are now typically understood as being produced by a pair of nearly symmetric, oppositely directed relativistic jets. While some these sources span megaparsecs, and are thus the largest physically connected structures in the universe, emitting regions identified as jets have now been found on all scales down to fractions of a parsec, and jets appear to be a common element of most (maybe all) types of active galactic nuclei (AGN). We first summarize key observations of different classes of cosmic radio jets, and describe how they may be connected. Theoretical models for the launching and propagation of extragalactic jets are briefly described. All of these models assume a magnetized plasma, which typically amounts to only a small fraction of the accreted gas, is ejected from the vicinity of a supermassive black hole. The extreme complexity of the relevant physics has demanded numerical simulations to examine non-linear effects on the stability of propagating jets, and some recent results from these efforts are summarized.

Table of Contents

INTRODUCTION: ``ANCIENT'' HISTORY

SOME KEY OBSERVATIONS AND IMPLICATIONS
Properties of extragalactic jets
The Fanaroff-Riley Dichotomy
Implications of Relativistic Motions

ANALYTICAL MODELS FOR JETS
The launching of extragalactic jets
The propagation and stability of extragalactic jets

NUMERICAL SIMULATIONS
The launching of extragalactic jets
The propagation and stability of extragalactic jets

CONCLUSIONS

REFERENCES

For a postscript version of the article, click here.

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