Fueling of Active Galactic Nuclei

Radiation pressure from the absorption and scattering of starlight by dust grains may be a crucial feedback mechanism in starburst galaxies and the self-gravitating parsec-scale disks that accompany the fueling of active galactic nuclei. I review the case for radiation pressure in both optically-thin and highly optically-thick contexts. I describe the conditions for which Eddington-limited star formation yields a characteristic flux of ∼ 10 L⊙ kpc , and I discuss the physical circumstances for which the flux from radiation pressure supported disks is below or above this value. In particular, I describe the young stellar disk on ∼ 0.1 pc scales at the Galactic Center. I argue that its bolometric flux at formation, ∼ 10 L⊙ kpc , and the observed stellar mass and scale height imply that the disk may have been radiation pressure supported during formation.