Imaging the invisible : constraining dark matter distributions in galaxy clusters using strong gravitational lensing

Abstract

In this thesis, I design and construct a Monte-Carlo gravitational lensing simulation that statistically studies the strong lensing of extended galactic sources by dark matter distributions in galaxy clusters, using recent work on cluster Abell 1689 as an empirical guide. By quantitatively comparing the quality of the lensed images created in the simulation to the giant lensed arcs observed by the Hubble Space Telescope around Abell 1689 and other similar clusters, and using an NFW analytic density profile to model the overall dark matter distribution, an upper limit is set on the scale of allowed deviations from a smooth NFW dark matter distribution. The maximum allowed mass-clumping is found to be on the order [approx.] 10⁸ M ... over volumes of order [approx.] 10kpc x 10kpc x 10kpc, indicative of a mostly smooth dark matter distribution with only relatively small deviations, much smaller than those of the distribution of conventional matter into galaxies.