Abstract
The hard-edged ionization cone seen by the HST imaging of NGC 4151 and the line-of-sight gas observed in some Seyfert 1 galaxies present a strong challenge for the simplest version of the Unified Model of AGN, which predicts that bi-conically shaped EELR can be observed only in type 2 objects and the line-of-sight to type 1 nucleus must be clear. To accommodate these rather contradictory requirements we suggest a modification of the shadowing/obscuration scenario. In our model the collimation of the ionizing radiation is provided by a partially neutral atmosphere surrounding the physically thin, dense torus. This atmosphere provides a natural way of producing wide angle ionization cones and at the same time allows for a relatively clear view of the central regions for some angles outside the cone edges. The model has an observationally testable predictions. Recently discovered nuclear disks in some elliptical galaxies hosting AGN may provide a natural way of supplying the gas for both the torus and the atmosphere surrounding it.
Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
