Analyzing the dust of the Nearby Universe

Abstract: The aim of this master thesis is to investigate the influence of intergalactic duston astronomical observations. The current cosmological paradigm of an acceleratingcosmic expansion is supported by observations of Type Ia supernovae. However, thelight emitted by these and other cosmological sources is not only redshifted by cosmicexpansion but will also interact with matter along the light path which affects the light.Especially intergalactic dust can lead to additional reddening and dimming of distantsources due to light scattering or absorption. This yields systematic contaminations tocosmological measurements. Using quasars as backlight sources we seek to estimate theattenuation of their observed spectra caused by intergalactic dust in order to determinethe existence and properties of the intergalactic dust. In this thesis we will analysethe methods and tools used as well as discussing the dust properties and how theyaffect the results. This thesis shows that intergalactic dust exist, and has a notableeffect on cosmological measurements and favors dust grains consisting of silicate witha size around 0.1 µm with Ωdust around 5 − 7 × 10^−6. The conclusion is in agreementwith previous studies of the same matter. With the increasing precision of cosmologicalmeasurements systematic effects such as intergalactic dust is a factor that has to betaken into account.