Résumé / Abstract Seminaire_IAP
« The AGN obscuring torus - end of the bagel paradigm? »

Moshe Elitzur
Dept. Physics Astron., Univ. Kentucky (Lexington, Kentucky, Etats-Unis d'Amérique)

The variety of observations of Active Galactic Nuclei (AGN) have been classified with a simple unified scheme: The nuclear activity is powered by a central massive black hole that drives radio emitting jets and ionizes surrounding line-emitting clouds. The whole system is surrounded by a dusty torus and the observer's orientation with respect to this obscuring torus determines the appearance of the AGN. Pole-on viewing gives rise to superluminal jets and Seyfert 1 line spectrum, edge-on results in extended radio lobes and Seyfert 2 lines. The torus is comprised of optically thick dusty clouds in a rotating configuration with roughly equal vertical and radial dimensions.
Although the observed IR is in broad agreement with the expected effects of the dusty torus, detailed properties of the spectral energy distribution (SED) posed difficult problems. The dynamical origin of the rotating cloud configuration, and especially its vertical support, present an even more serious challenge. We have recently developed a formalism to handle radiative transfer in clumpy media and in this talk I show that the SED problems find a natural explanation if the dust is contained in about 5--10 clouds along radial rays through the torus. Furthermore, the properties of the model SED may also provide the answer for the torus dynamical origin.
vendredi 10 février 2006 - 11:00
Salle des séminaires Évry Schatzman, Institut d'Astrophysique de Paris
Page web du séminaire / Seminar's webpage