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

Reprinted with kind permission from Annual Reviews, 4139 El Camino Way, Palo Alto, California, USA

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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

¹ The US Government has the right to retain a nonexclusive, royalty-free license in and to any copyright covering this paper. Back.

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.