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
Famous quotes containing the words types of, types, active and/or galaxy:
“Science is intimately integrated with the whole social structure and cultural tradition. They mutually support one other—only in certain types of society can science flourish, and conversely without a continuous and healthy development and application of science such a society cannot function properly.”
—Talcott Parsons (1902–1979)
“As for types like my own, obscurely motivated by the conviction that our existence was worthless if we didn’t make a turning point of it, we were assigned to the humanities, to poetry, philosophy, painting—the nursery games of humankind, which had to be left behind when the age of science began. The humanities would be called upon to choose a wallpaper for the crypt, as the end drew near.”
—Saul Bellow (b. 1915)
“The sense of an entailed disadvantage—the deformed foot doubtfully hidden by the shoe, makes a restlessly active spiritual yeast, and easily turns a self-centred, unloving nature into an Ishmaelite. But in the rarer sort, who presently see their own frustrated claim as one among a myriad, the inexorable sorrow takes the form of fellowship and makes the imagination tender.”
—George Eliot [Mary Ann (or Marian)
“for it is not so much to know the self
as to know it as it is known
by galaxy and cedar cone,
as if birth had never found it
and death could never end it:”
—Archie Randolph Ammons (b. 1926)