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dc.contributor.authorHiggins, Alasdairen
dc.date.accessioned2018-01-31T11:45:28Z
dc.date.available2018-01-31T11:45:28Z
dc.date.issued2003
dc.identifier.urihttp://hdl.handle.net/1842/28234
dc.description.abstracten
dc.description.abstractI present an analysis of techniques used to determine the mass power spectrum from observations of the intergalactic medium.en
dc.description.abstractSimple Monte Carlo simulations are presented which clarify some of the problems which must be overcome when attempting any inversion process. The 1 dimensional flux power spectrum is dependent on both the clustering of the absorption features and on the scaling relations existing between the dark matter and baryon distributions.en
dc.description.abstractMore realistic simulated spectra are used to illustrate differences in the mean flux power spectrum for a range of cosmologies and the ratio of the 1 dimensional linear mass and flux power spectra. The mass distribution is much more dependent on cosmological parameters than the flux power spectrum, highlighting the very accurate measurements of the latter quantity required for an accurate recovery of the mass density power spectrum.en
dc.description.abstractThese spectra are further analysed by deconvolution into Voigt profiles. This technique is shown to be an excellent approximation, in spite of the current cosmic web paradigm of the Ly-a forest. However the power spectrum of the positions of these fitted lines is shown to be a very poor indicator of the underlying mass density field.en
dc.description.abstractInferring the 3 dimensional forms of power spectra from 1 dimensional data is shown to be problematic. This, coupled with analysis of the correlation matrix of the flux power spectrum, casts doubts on the reliability of the error analysis presented in the literature.en
dc.publisherThe University of Edinburghen
dc.relation.ispartofAnnexe Thesis Digitisation Project 2017 Block 16en
dc.relation.isreferencedbyAlready catalogueden
dc.titleUsing the Lyman-α forest to determine the power spectrum of mass density perturbationsen
dc.typeThesis or Dissertationen
dc.type.qualificationlevelen
dc.type.qualificationnamePhD Doctor of Philosophyen


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