Dust in active galactic nuclei and quasars

Radiation from many active galaxies and possibly quasars shows evidence of dust extinction. Much of the obscuring material is apparently located close to the line-emitting gas. An asymmetric geometrical configuration viewed from various angles could explain observed differing amounts of reddening suffered by broad-line regions, narrow-line regions, and continua. Because active galaxy dust characteristics may differ significantly from those of interstellar material in the Galaxy, it is advisable to base extinction corrections on actual observations across relevant spectral ranges. Potential procedures for establishing useful corrections and inferred dust distributions are discussed. 124 references