Accretion Corona Immersed in Disk Radiation Fields

Abstract

We theoretically examined an accretion-disk corona, which is infalling toward the central black hole. The corona was supposed to be initially at rest far from the center. It was also assumed to be both geometrically and optically thin. During infall above and below the disk, the corona is suffered from the disk radiation fields. When the accretion disk is less luminous, the corona gas freely infalls to the center. When the accretion disk is sufficiently luminous, on the other hand, the corona gas gains angular momentum from the underlying disk via radiation drag. As a result, the infall of the corona gas is suppressed and the corona gas tends to corotate with the disk. When the disk is highly luminous, the infall of the corona gas stops in the inner disk and the corona gas may blow off from the disk as a radiatively driven wind.