Galaxies form and live inside dark matter haloes. As a consequence, they are exposed to the tidal fields generated by the surrounding matter distribution: this imprints a preferential direction to... Show moreGalaxies form and live inside dark matter haloes. As a consequence, they are exposed to the tidal fields generated by the surrounding matter distribution: this imprints a preferential direction to the galaxy shapes, which leads to a coherent alignment on physically close galaxies, called intrinsic alignment. Intrinsic alignment is an important contaminant to weak lensing, which instead uses the correlation of galaxy shapes caused by the lensing effect of the matter distribution along the line of sight to infer the amount and the distribution of matter in the Universe.This dissertation studies the dependence of intrinsic alignment on galaxy properties such as luminosity, redshift and halo mass, using different techniques to measure it. It presents a model to account for the scale and sample dependence of the intrinsic alignment signal when modelling it in weak lensing studies. It also investigates the amount of biasing that incorrect modelling of intrinsic alignment would induce in the inferred cosmological parameters for ongoing and future surveys. The potential of weak lensing magnification is also explored to help constrain the cosmological parameters in upcoming surveys. Show less
Johnston, H.; Joachimi, B.; Norberg, P.; Hoekstra, H.; Eriksen, M.; Fortuna, M.C.; ... ; Tallada-Crespí, P. 2021
