Stochastic nonlinear self-oscillatory model of an accretion disk for the X-ray bursting of the microquasar GRS 1915+105

Abstract

. The observed light curves of the microquasar GRS 1915+105 show three main characteristics, namely chaotic, stochastic and semi-stochastic (or nonstochastic). In order to probe the origin causing these different features, we propose a stochastic nonlinear self-oscillatory model of an accretion disk, and use its oscillating luminosities with different noise strengths and nonlinear factors to simulate the observational variability, and compare their correlation dimensions calculated by a nonlinear time series analysis. It is shown that when the stochastic noise strength is small and the nonlinear factor is large, the luminosity curves show chaotic behavior. On the contrary, it shows stochastic or semi-stochastic behavior when a stochastic factor dominates. The simulated data exhibits the same nonlinear and random characteristics as the observational sequences, and their corresponding correlation dimensions are also consistent. This indicates that the X-ray bursting of the microquasar should be related to a nonlinear self-oscillation of the accretion disk.