Appearance of an accretion disk perturbed by fractional Brownian Motion   density
  This paper aims to investigate/map the effects that perturbations applied to an accretion disk might produce on the registered Light Curves (LC). The case of accretion disks around supermassive active black holes (AGNs) is studied with the goal to explain some of the statistical properties of the observed IntraDay Variability (IDV). The region producing optical IDV is perturbed by allowing it to develop a mass density of a fractional Brownian Motion-like type. The light curves and spectral slopes are calculated and compared to observational data for different Hurst parameters. The spectral slopes of the simulated light curves vary in the range $(0.4,2.5)$. The agreement with observational data shows that a magnetized disk subjected to stochastic perturbations can produce some of the features observed in the light curves. 
Gabriela Mocanu, Norbert Magyar, Anabele Pardi, Alexandru Marcu
astro-ph.HE astro-ph.GA astro-ph.SR