Radiative Avalanche Driven by Spherical Starbursts

We examine a radiative avalanche for the case of spherically distributed sources. A radiative avalanche is a new mechanism, in which the mass-accretion of the nuclear disk is driven via radiation drag exerted by stellar radiation from circumnuclear starburst regions, and which is expected to be a link between starburst activities and AGNs. The results of the present spherical case are qualitatively similar to those of the ring-like case. However, the solid angle subtended by the starburst region is large and the radiation field of the starburst region has no angular momentum, which are in favor for the avalanche model. In addition, an avalanche can take place continuously from the outside to the inside of the starburst region in the spherical case.