Exploring the Dark and Dusty Universe with Gravitational Lensing – Niels Bohr Institute - University of Copenhagen

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Exploring the Dark and Dusty Universe with Gravitational Lensing

Ph.d.-forsvar; Árdís Elíasdóttir, Niels Bohr Institutet

In this thesis gravitational lensing, the deflection of
light caused by the curvature of spacetime, is used as a tool to
study the dark and distant universe. The first part presents the
first systematic study of the dust extinction properties in lensing
galaxies using multiply imaged gravitationally lensed quasars. It is
shown that the extinction properties can vary greatly from those of
the Milky Way. The impact this can have on future supernovae dark
energy missions is discussed. The second topic of the thesis is dark
matter in galaxies and clusters. It starts with a theoretical study
of the strong lensing properties of two different types of dark
matter profiles motivated by simulations. Next, numerous strong
lensing constraints are used to construct a mass map of the galaxy
cluster Abell 2218, tracing the dark matter distribution of the
cluster. The vast majority of the dark matter is found to reside in
a smooth cluster component, perturbed by the smaller dark matter
halos of the cluster galaxies. The lensing constraints are shown to
be sensitive to substructure, dark or luminous, if the substructure
is massive or locally perturbs a system.