Conclusions

Abstract

In this work, the five- and seven-year observations of the CMB by the WMAP satellite were analysed in detail by means of the scaling index method. The basic ideas for this method stem from the calculation of dimensions of strange attractors in nonlinear time series analysis. Scaling indices are able to identify and characterise the structural components of a given data set. One the one hand, the tests for deviations from the standard model were performed by comparing the data sets to simulations of Gaussian random fields mimicking the properties of the $\Lambda$CDM model, which represents the standard approach in CMB investigations. On the other hand, a novel approach, namely the method of surrogates, was developed in this work, which offers the possibility to analyse the CMB in a completely data-driven way. Here, the basic idea is the construction of surrogate data sets, which are generated by dedicated shuffling of the Fourier phases of the original data map.