|Annu. Rev. Astron. Astrophys. 1980. 18:
Copyright © 1980 by . All rights reserved
But it is an error to suppose, because we resolve to confine our attention to a certain number of the properties of an object that we therefore conceive, or have an idea of, the object denuded of its other properties.
J.S. Mill, Logics and Mathematics Based on Observation
5.1. Characteristic Scales
Some typical scales observed in extended radio sources and their environment are compared in Table 2. Note the similarities between the characteristic radio and optical scales. These suggest that the radio-source phenomenon may be intimately connected with properties of the source environment. Here we shall consider possible relationships.
|~ 10-3||Nuclear nonthermal continuum|
|~ 10-1||Flat-spectrum core||Broad (permitted) line region|
|~ 103||Steep-spectrum core||Narrow (forbidden) line region|
|~ 105.2||Extended radio source||Galactic halo|