Power Spectrum and Intermittency of Ly(alpha) Transmitted Flux of QSO HE 2347-4342

We have studied the power spectrum and the intermittent behavior of the fluctuations in the transmitted flux of HE 2347-4342 Ly(alpha) absorption in order to investigate if there is any discrepancy between the (lambda)CDM model with parameters given by the WMAP and observations on small scales. If the nonGaussianity of the cosmic mass field is assumed to come only from halos with a universal mass profile of the (lambda)CDM model, the non-Gaussian behavior of mass field would be effectively measured by its intermittency, because intermittency is a basic statistical feature of the cuspy structures. We have shown that the Ly(alpha) transmitted flux field of HE 2347-4342 is significantly intermittent on small scales. With the hydrodynamic simulation, we demonstrate that the (lambda) CDM model is successful in explaining the power spectrum and intermittency of Ly(alpha) transmitted flux. Using statistics ranging from second to eighth order, we find no discrepancy between the (lambda)CDM model and the observed transmitted flux field and no evidence to support the necessity of reducing the power of density perturbations relative to the standard (lambda)CDM model up to comoving scales as small as about 0.08 h-1 Mpc. Moreover, our simulation samples show that the intermittency exponent of the Ly(alpha) transmitted flux field is probably scale-dependent. This result is different from the prediction of a universal mass profile with a constant power index of the central cusp. The scale dependence of the intermittency exponent indicates that the distribution of baryonic gas is decoupled from the underlying dark matter.