narrow-line region (NLR) → περιοχή των στενών γραμμών
extended narrow-line region (ENLR)
The narrow-line region is the most extensive part of the AGN and envelops all the other components. Like the other parts, it is illuminated by the central engine. Bearing in mind the geometry of the dust torus, describe what the NLR might look like if a spaceship could get close enough to see it.
Introduction to active galaxies - OpenLearn - Open University