Baryonic effects on cosmological large scale structure

UBC Physics & Astronomy Astronomy Colloquium on November 23, 2020. Presented by Simon Foreman (Perimeter).

Upcoming measurements of large-scale clustering in the universe promise to provide new insights into cosmology and fundamental physics, but a variety of modelling and analysis challenges must be addressed if this promise is to be fully realized. In this talk, I will discuss one such challenge: the modelling uncertainty associated with so-called "baryonic effects," specifically the influence of gas dynamics and feedback from active galactic nuclei on the large-scale distribution of matter. After reviewing the broad picture of these effects provided by hydrodynamical simulations, I will present case studies of their impact on (1) neutrino mass measurements using gravitational lensing of the cosmic microwave background, and (2) generic three-point clustering statistics. I also briefly review different observational avenues for constraining these effects, which will likely play an important role in the success of upcoming cosmological surveys.