| This thesis centers around work which was performed in the lead up to and during analysis of high resolution cosmic microwave background (CMB) data coming from the South Pole Telescope and from the Planck satellite. Analysis of such data necessitates modeling of extra-galactic foregrounds, and here we develop a model for these foregrounds for use with current data. This model is shown to be both necessary and sufficient for unbiased estimation of cosmological parameters. Additionally, we develop a novel method for using auxiliary data in the form of galaxy number counts to put priors on certain components of this model. Finally, we perform an analysis of CMB data, taking into account these extra-galactic foregrounds, to calculate new constraints on hypothetical particles like axions or axion-like particles. We find new data from Planck and from measurements of primordial deuterium newly rule out some theoretically interesting regions of parameter space. In addition, we show that in a more speculative scenario which includes the presence of both axions and other dark radiation, some of these regions are again allowed and could explain hints of high primordial helium fraction, or could allow one or two thermalized sterile neutrinos to exist. |
