Towards Next-Generation Millimeter-Wave Cosmology from the Atacama

Abstract

We expect both exciting new insights and analysis challenges from ground-based CMB surveys in the next decade, such as from the existing Atacama Cosmology Telescope (ACT) and the South Pole Telescope (SPT), as well as from the upcoming Simons Observatory and CMB-S4. In this thesis, we demonstrate the utility of cross-correlating data from a large aperture instrument (ACT) with data from the Atacama B-mode Search (ABS), a small aperture instrument equipped with a half-wave plate, to target the polarization at large scales from the ground. This strategy is able to significantly suppress atmospheric contamination of the resulting power spectrum, and we expect to employ it in upcoming surveys.We then implement a complete Planck satellite analysis pipeline that reproduces both the intermediary and cosmological results of the PR3 data release. This effort is required for current and future joint analysis efforts of the Planck data with new, large-sky-fraction observations such as from ACT and Simons Observatory. We also present new simulated catalogs and maps of radio galaxies, which are consistent with the latest radio data (unlike pre-existing works). These radio sources present a challenge for a variety of cosmological analyses in the millimeter. These maps are also correlated with the large-scale structure through the Websky simulations.Finally, we provide new constraints on the interaction cross section between dark matter and baryons in the early Universe, by combining ACT DR4 data with Planck PR3. We show that the addition of small-scale data from ACT nearly halves the allowed parameter space of dark matter-baryon interaction models, compared to previous work using Planck alone.