Institute for Advanced Study/Princeton University Early Universe/Cosmology Lunch Discussion
Simulating the SZ effect using baryonification
Gravity-only simulations have been crucial for predicting the matter power spectrum, but they assume baryons have little influence on large-scale structure formation—a notion that has been proven incorrect. With upcoming surveys like LSST and the Simons Observatory, addressing systematic errors in theoretical predictions is essential. In this talk, I will present how the new baryonification model, BCM24, can be used to simulate astrophysical effects in N-body simulations and forward-model both the kinematic Sunyaev-Zel’dovich (SZ) effect and gas fraction measurements jointly. Specifically, I will demonstrate that BCM24 successfully reproduces dark matter, stellar, and thermodynamic (gas density and pressure) profiles from the Flamingo hydrodynamical simulation and aligns with various observational datasets, while also matching the power spectrum from Flamingo. Building on this validation, I will show that the most recent SZ measurements from the Atacama Cosmology Telescope (ACT) can be reproduced using realistic parameters, yielding a final matter power spectrum that helps reduce the S8 tension.