NEW EVIDENCE FOR AN ANISOTROPIC RADIATION-FIELD IN NGC 5252

Observational evidence accumulated over the last decade strongly suppo rts the idea that the ionizing radiation field in active galactic nucl ei (AGNs) is anisotropic. Here we report on new evidence for this anis otropy in the particular case of the Seyfert 2 galaxy NGC 5252. H I ob servations of this galaxy reveal neutral gas surrounding the nucleus b ut located outside the bicone of ionized gas that notably characterize s this object. The neutral gas is at a distance from the nucleus where it could be reached by the ionizing radiation if this were isotropica lly distributed.