1998A&A...336..823M

The use of adaptive optics has allowed to reach in the infrared an angular resolution around 0.35", allowing to study the temperature, mass and distribution of the dust component within the 400pc radius central region of NGC 7469. We have obtained L and L' band images which show an unresolved core (r<55pc) embedded in an extended emission component. Not to mention the ring of star formation, known to be present at r∼1.5", which cannot be studied from this data set because of its quite low surface brightness and will not be discussed here. We find that about 55% of the 3.5 and 3.8µm flux across the 1.4"x1.4" central region arises from the unresolved core. The hot and warm dust grain density in the extended component follows an r^–1.5 law, and the dust temperature ranges from 900K (r∼130pc) to ∼300K (r∼400pc). The mass of hot (T=900K) dust within a r∼200pc central region is ∼0.05M_☉ and it accounts for 36% of the 2.2µm emission in this region. These results are in good agreement with a composite model of active nucleus including a parsec scale dusty torus surrounded by an extended hot dust region located in the NLR and heated by the central engine.