Supernova Explosions in Accretion Disks in Active Galactic Nuclei: Three-dimensional Models

Supernova (SN) explosions can potentially affect the structure and evolution of circumnuclear disks in active galactic nuclei (AGN). Some previous studies have suggested that a relatively low rate of SN explosions can provide an effective value of alpha viscosity between 0.1 and 1 in AGN accretion disks within a 1 pc scale. In order to test this possibility, we provide some analytic scalings of the evolution of an SN remnant embedded in a differentially rotating smooth disk. We calibrate our estimates using three-dimensional hydrodynamical simulations where the gas is modeled as adiabatic with index gamma. Our simulations are suited to include the fact that a fraction of the momentum injected by the SN escapes from the disk into the corona. Based on these results, we calculate the contribution of SN explosions to the effective alpha viscosity, denoted by alpha(SNe), in a model AGN accretion disk, where accretion is driven by the local viscosity alpha. We find that for AGN galaxies with a central black hole of similar to 10(8)M(circle dot) and a disk with viscosity alpha=0.1, the contribution of SN explosions may be as large as alpha(SNe) similar or equal to 0.02, provided that gamma similar or equal to 1.1. On the other hand, in the momentum conservation limit, which is valid when the push by the internal pressure of the SN remnant is negligible, we find alpha(SNe) less than or similar to 6 x 10(-4).