Noise, friction and the radial-orbit instability in anisotropic stellar systems: stochastic N-body simulations

By means of numerical simulations we study the radial-orbit instability in anisotropic self-gravitating N-body systems under the effect of noise. We find that the presence of additive or multiplicative noise has a different effect on the onset of the instability, depending on the initial value of the orbital anisotropy.