| One of the greatest quandaries in modern cosmology is understanding the nature of dark matter. Although not visibly observable, dark matter influences the evolution of the universe through its empirical gravitational effects. As a result, gravitational lensing is the only unambiguous method of accurately measuring this matter independently of its type, symmetry, and dynamical state. As the most massive, recently formed, bound structures in the universe, galaxy clusters retain information about their formation history (Bradac et al., 2004) and possess a dynamic time scale on the order of the age of the universe. Therefore, galaxy clusters are the ideal cosmological laboratories for constraining cosmology, exploring the nature of dark matter, and testing theories of formation and evolution of structures (Xue & Wu, 2002; Ghigna et al., 1998; Andersson & Madejski, 2004).; For this thesis, software has been developed to provide a precise and efficient method of modeling cluster lenses without assumptions relating the large scale cluster dark matter to the observed light. The wide-field images of the Abell 1689 cluster obtained by the HST Advanced Camera for Surveys (ACS) reveal numerous strongly lensed galaxies. With this plethora of strongly lensed images as constraints, a robust cluster mass model can be derived using a freely varying cluster large-scale halo component derived from a perturbed cuspy profile (Navarro, Frenk, & White, 1997) as well as a component based on the cluster galaxy light. Monte Carlo simulations are also performed to explore constraints on cosmology and to better understand the modeling systematics related to the image positional errors, multiple image system dependence, as well as the WMAP cosmological constraints.; Finally, the combined resolution and sensitivity provided by ACS imaging in conjunction with the amplification by the cluster gravitational lensing provide the detail necessary for the robust cluster modeling and exploration of the high-redshift universe through detailed source reconstruction. In particular, the lens magnification of high-redshift galaxies propels their images into the observation range, producing a high-resolution view of the distant universe which is normally beyond observability except under circumstances such as these. |
