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dc.contributor.authorRobison, Bailey 18:51:07 (GMT) 18:51:07 (GMT)
dc.description.abstractDark matter haloes are expected to have a triaxial shape, appearing elliptical in projection. Understanding the orientation of these dark matter haloes, and how they are aligned, has implications for theories of structure formation in the universe. Additionally, a better understanding of halo alignment will allow us to account for intrinsic alignments and improve future weak lensing studies. We measure dark matter halo ellipticity using weak galaxy-galaxy lensing. We study the anisotropic shear around luminous red galaxies (LRGs) from the Baryon Oscillation Spectroscopic Survey (BOSS), using galaxies from the Canada-France Imaging Survey (CFIS) as background source galaxies. By aligning with the major axis of the galaxy light before measuring the shear, we can stack many lens galaxies to obtain a detection of halo ellipticity. We model the dark matter mass distribution as a multipole expansion, with an isotropic monopole component and a quadrupole that accounts for the angular dependence and ellipticity. We calculate 6 quadrupole estimators, which are designed to measure anisotropic lensing signal while minimising any isotropic contributions. Taking the results from these estimators into account, we obtain a mean halo ellipticity of e = 0.226 ± 0.102. We also study the lensing signal when aligning with filaments, using pairs of LRGs as a proxy. This also yields a detection of dark matter anisotropy. A meaningful measure of ellipticity along the filaments will require further development of the model to account for anisotropy on larger scales.en
dc.publisherUniversity of Waterlooen
dc.subjectdark matteren
dc.subjectgravitational lensingen
dc.subjectweak lensingen
dc.subjectdark matter haloen
dc.titleThe Shape of Dark Matter Haloes: Results from Weak Lensingen
dc.typeMaster Thesisen
dc.pendingfalse and Astronomyen of Waterlooen
uws-etd.degreeMaster of Scienceen
uws.contributor.advisorHudson, Michael
uws.contributor.affiliation1Faculty of Scienceen

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