Toward a mass-limited catalog of galaxy clusters from the Atacama Cosmology Telescope

The Atacama Cosmology Telescope (ACT) is a six meter observatory in the Andes of northern Chile. It is currently in its third season of operation, observing the cosmic microwave background (CMB) with about 1000 detectors each at 148 GHz, 218 GHz, and 277 GHz. Capable of producing high sensitivity maps of the CMB at arcminute resolution, the ACT will contribute to our knowledge of cosmology by constraining the parameters describing the early universe as well as by studying its subsequent evolution. One of the more important tools for investigating the latter will be the Sunyaev-Zel'dovich (SZ) effect, by which large clusters of galaxies leave distinct imprints in the CMB, the strength of which is nearly independent of redshift. In this dissertation, we present maps of the first SZ clusters to be detected by the ACT, showing that we are beginning to reach our objective of creating a large, mass-limited catalog of clusters for probing the growth of structure in the universe. Extensive data analysis is required to produce our CMB maps, so, after describing the telescope itself, much of the dissertation is devoted to presenting some of the mapmaking elements. In particular, we have developed a pipeline which specializes at removing atmospheric contamination from the data to produce small, clean maps suitable for cluster analysis. It has also been used to make high precision beam maps, crucial for interpreting all of the measurements made by the ACT.