Where are the Broad Lines in Seyfert 2S?
The unified model for Seyfert 2s postulates that these galaxies are in fact normal Seyfert is whose innermost regions are hidden from a direct view by an opaque torus. Galaxies seen from a line-of-sight within the opening angle of this torus have the central continuum source and the Broad Line Region unobstructed, and are classified as Seyfert 1/QSO. In Seyfert 2s, on the other hand, periscopic views of the hidden nucleus may be obtained through scattering of the nuclear light in the extranuclear regions. If this model is correct, the Blue and Featureless Continuum observed in many Seyfert 2s is simply a mirror image of the obscured nucleus. In this case, the light from the Broad Line Region must also be reflected towards the observer. Seyfert 2s should therefore exhibit broad lines in their spectrum, which, by definition, they do not! In this contribution we examine this issue and the complications it brings to the basic unification picture of Seyfert galaxies. We fail to find a consistent explanation for this question in the framework of the unified model. An alternative “modified-unified model” for Seyfert 2s is proposed.
KeywordsUnify Model Equivalent Width Broad Line Seyfert Galaxy Broad Component
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