Quasars Classes and Their Relationships

摘要: Most of the questions in this chapter deal with sources that do not show “classical” broad emission-line spectrum characterizes majority known AGNs at high and low redshift. If represents a “parent population” AGNs, is apparent absence lines result obscuration, orientation, or different physical conditions? Can all subclasses be unified under AGN umbrella? With unification scheme set place assumed to fundamentally correct, there are least four overarching questions: type-2 possess an obscured broad-line region? Or how can we distinguishing without region if they exist? Where end quasar activity? The luminous so-called low-ionization nuclear regions (LINERs), but it legitimate ask true AGNs.