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.
For a postscript version of the article, click
here.
INTRODUCTION: ``ANCIENT'' HISTORY
SOME KEY OBSERVATIONS AND IMPLICATIONS
ANALYTICAL MODELS FOR JETS
NUMERICAL SIMULATIONS
CONCLUSIONS
REFERENCES
