3:30–4:30 pm ERC 161
J. Colin Hill (Columbia University) "Searching for New Physics in the Universe's Oldest Light with the Atacama Cosmology Telescope"
I will discuss recent and ongoing work focused on attempts to restore concordance amongst cosmological data sets, motivated by discrepancies amongst some measurements of the cosmic expansion rate (H_0) and the matter clustering amplitude (S_8). Particular attention will be paid to models invoking new physics at or prior to recombination, including quasi-accelerating early dark energy (EDE) models and a newly developed extension of this scenario featuring interactions between the EDE field and the dark matter. In particular, I will discuss constraints on these models derived using the latest data from the Atacama Cosmology Telescope (ACT), as well as independent cross-checks derived using public data from the South Pole Telescope. I will conclude with a look ahead to forthcoming CMB measurements from ACT, which will provide a powerful test of these scenarios in the low-noise, high-resolution regime.
