Institute for Advanced Study Informal Astrophysics Seminar

I will give a tour through a variety of results on how precision cosmological data can test for the consequences of a light scalar in the early universe, such as an axion or a curvaton. Observable consequences could include altered CMB peak structure, suppressed matter power on small scales, and isocurvature perbturbations. I'll discuss constraints from Planck and WiggleZ, the prospects for a future CMB-S4 type experiment. I will conclude with a snapshot of ongoing work with undergraduate students at Haverford college, including work to forecast the prospects of large galaxy surveys for constraining axions, and separate work to improve the treatment of axion perturbation evolution in cosmological Boltzmann codes.