Annu. Rev. Astron. Astrophys. 1997. 35: 607-36
Copyright © 1997 by . All rights reserved

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PARSEC-SCALE JETS IN EXTRAGALACTIC RADIO SOURCES 1

J. Anton Zensus


National Radio Astronomy Observatory, 2 Charlottesville, Virginia 22903


Abstract. Observations of parsec-scale radio jets associated with active galactic nuclei are reviewed, with a particular emphasis on high-luminosity core-dominated sources where the most detailed information on individual objects exists. Extensive imaging surveys with very long baseline interferometry (VLBI) have made possible a morphologic classification of compact radio sources and systematic studies of the statistics of apparent (often faster-than-light) motions found in an increasing number of sources. VLBI monitoring studies at centimeter and millimeter wavelengths, enhanced by spectral and polarization imaging, of representative types of AGN can discriminate detailed physical models. The observations are especially discussed in light of the variant of the relativistic beaming model that explains kinematic, spectral, and polarization properties of parsec-scale jets through shocks in an underlying continuous jet flow.


Key words: compact radio sources, radio source morphology, radio jets, VLBI jets, superluminal motion, jet models


Table of Contents

INTRODUCTION

MORPHOLOGY
High-Luminosity Core Dominated Objects
FR II Radio Galaxies and Quasars
FR I Radio Galaxies and Quasars
Compact Steep Spectrum Sources and Compact Symmetric Objects

STRUCTURAL VARIATIONS
Apparent Superluminal Motion
Curved Trajectories
Variable Component Speeds
Broadband Activity and Emergence of New Jet Components

PHYSICAL CONDITIONS IN THE PARSEC-SCALE JETS
Helical Jets
Spectral Properties
Polarization Properties

CONCLUSION

REFERENCES



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2 The National Radio Astronomy Observatory is a facility of the National Science Foundation, operated under cooperative agreement by Associated Universities, Inc. 22-009-526. Back.

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