State of the Universe

Inferring the impact of feedback on the matter distribution using the Sunyaev Zel'dovich effect

by Mr. Shivam Pandey (U Penn)

Friday, March 17, 2023 from to (Asia/Kolkata)
at Zoom : https://us02web.zoom.us/j/82512956967?pwd=angyQ0ZDdHZUdzFUbjkybmxsWFNFUT09 Meeting ID: 825 1295 6967 Passcode: 384194
Description
Feedback from active galactic nuclei and stellar processes changes the matter distribution on small scales, leading to significant systematic uncertainty in weak lensing constraints on cosmology. In this talk, I will describe how the observable properties of group-scale halos can be used to constrain the impact of feedback on the matter distribution using Cosmology and Astrophysics with Machine Learning Simulations (CAMELS). By extending the results of previous work to smaller halo masses and higher wave numbers, k, we find that the baryon fraction in halos contains valuable information about the impact of feedback on the matter power spectrum. We will also explore how the thermal Sunyaev Zel'dovich (tSZ) signal from group-scale halos can provide similar information. Using recent Dark Energy Survey (DES) weak lensing and Atacama Cosmology Telescope (ACT) tSZ cross-correlation measurements and models trained on CAMELS, we obtain 10% constraints on the effects of feedback on the power spectrum at k ~ 5 h/Mpc. I will also demonstrate that with future surveys, it will be possible to constrain baryonic effects on the power spectrum to O(<1%) at k = 1 h/Mpc and O(3%) at k = 5 h/Mpc using the methods introduced here.