Influence of noise on statistical properties of nonhyperbolic attractors

We analyze effects of hounded white and colored noise on nonhyperbolic chaotic attractors in two-dimensional invertible maps. It is shown that first the nonhyperbolic nature is kept even in the presence of strong noise, but secondly already due to weak noise some propel-ties of nonhyperbolic chaos can become similar to those of hyperbolic and almost hyperbolic chaos. We also estimate the stationary probability measure uf noisy nonhyperbolic attractors. For this purpose two different methods for calculating the probability density are applied and the obtained results are compared in detail.