The bilateral symmetry around active galaxies was discovered in the radio continuum in the 1950s. It has since been found to manifest itself throughout the electromagnetic spectrum in the continuum as well as lines, on scales from subparsec to megaparsecs. Detailed observations have often led to classification schemes based on different length- and time-scales, and types and stages of activity. Consolidation of continuum and line observations in total and polarized intensities in various bands of the electromagnetic spectrum from gamma-rays to radio should lead to a more complete picture, unifying these schemes into a physical whole. We review these observations of active galaxies and their current models, and how well the two fit together. Our emphasis throughout is on bilateral structure in and around active galaxies. (C) 1998 Elsevier Science B.V. All rights reserved. [References: 582]
展开▼
