Types of Active Galaxy
It is convenient to divide AGN into two classes, conventionally called radio-quiet and radio-loud. In the radio-loud objects a contribution from the jet(s) and the lobes they inflate dominates the luminosity of the AGN, at least at radio wavelengths but possibly at some or all others. Radio-quiet objects are simpler since jet and jet-related emission can be neglected.
AGN terminology is often confusing, since the distinctions between different types of AGN sometimes reflect historical differences in how objects were discovered or initially classified, rather than real physical differences.
Read more about this topic: Active Galactic Nucleus
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