title: Different aspects of the interplay between light and the large-scale structure of the Universe
creator: Merkel, Philipp M.
subject: ddc-530
subject: 530 Physics
description: The main subject of this thesis is the influence of intrinsic alignments on weak lensing measurements. One possible source of intrinsic alignments are correlations in the angular momenta of neighbouring galaxies. Employing an improved ansatz for the angular momentum correlation function I show that the typical correlation length of Milky Way-sized haloes is about 1 Mpc/h which is slightly smaller than earlier work in this field suggested. Establishing the constitutive formalism to describe intrinsic alignments consistently in the framework of 3d cosmic shear I compute the resulting covariance matrices of different alignment types. For a Eucild-like survey it turns out that intrinsic alignments are more than one order of magnitude smaller than the lensing signal. In addition the parameter estimation bias in a two-dimensional non-tomographic weak lensing measurement is computed. The matter density Omega_m and the normalization of the linear matter power spectrum sigma_8 are most severely biased if intrinsic alignments are described by an angular momentum based alignment model. In the second part of my thesis I address secondary anisotropies of the cosmic microwave background: weak gravitational lensing and the nonlinear integrated Sachs-Wolfe (iSW) effect. The characteristic imprint of lensing can be used to reconstruct the lensing potential power spectrum. I show how this reconstruction is biased in the presence of primordial non-Gaussianities. For current values of f_NL, however, the bias is completely negligible on all but the largest angular scales. Finally, a novel analytical approach for the computation of the nonlinear iSW effect valid in the translinear regime is presented. It allows to identify two distinct contributions: the change of the gravitational self-energy density of the large-scale structure with (conformal) time and the Birkinshaw-Gull effect.
date: 2013
type: Dissertation
type: info:eu-repo/semantics/doctoralThesis
type: NonPeerReviewed
format: application/pdf
identifier: https://archiv.ub.uni-heidelberg.de/volltextserverhttps://archiv.ub.uni-heidelberg.de/volltextserver/15710/1/Dissertation_Philipp_M_Merkel.pdf
identifier: DOI:10.11588/heidok.00015710
identifier: urn:nbn:de:bsz:16-heidok-157100
identifier:   Merkel, Philipp M.  (2013) Different aspects of the interplay between light and the large-scale structure of the Universe.  [Dissertation]     
relation: https://archiv.ub.uni-heidelberg.de/volltextserver/15710/
rights: info:eu-repo/semantics/openAccess
rights: http://archiv.ub.uni-heidelberg.de/volltextserver/help/license_urhg.html
language: eng