X-ray Fluctuations from the Slim Disk

The responses of perturbations added into the optically thick, advection-dominated accretion disk (ADAD), what we call the slim disk (SD), are investigated through numerical simulations. Although it is proposed that the SD is thermally stable, I find that a perturbation added into the disk is not rapidly damped and moves through the disk in its free-fall time. After the perturbation moves, the global structure of the disk does not vary very much. These facts may account for the substantial variability of the X-ray luminosities of stellar super-luminal jet sources (SLJSs) and Narrow-Line Seyfert 1s (NLS1s).