KeywordsPhysics, Astronomy and Astrophysics.
MetadataShow full item record
PublisherThe University of Arizona.
RightsCopyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author.
AbstractI study the weak nonlinear regime of structure formation using high resolution and high signal-to-noise ratio (S/N) samples of Quasi Stellar Objects' (QSOs) Lyα transmission spectra. Using a space-scale decomposition, the Discrete Wavelet Transform (DWT), I show that the field traced by Lyα transmission flux is intermittent on scales less than 2000 km/s. The distribution of the local power of fluctuations is spiky with almost no power between the spikes. This spike-gap-spike feature gets more pronounced on smaller scales (128-16 km/s). This feature contradicts the predictions of the correlation hierarchy model on small scales ( < 64 km/s). Intermittency renders lower order statistics, like the power spectrum of fluctuations, ineffective in describing an intermittent field and discriminating between various structure formation models. I show that the structure functions and the intermittent exponent are not only able to quantitatively differentiate between different dark matter models but also qualitatively describe the nature of non-Gaussianity. The structure functions and the intermittent exponent are powerful tools for describing an intermittent field. Intermittency opens a new window in the study of the nonlinear evolution of structure in the universe.
Degree ProgramGraduate College