Inferring the impact of feedback on the matter distribution using the Sunyaev Zel'dovich effect: Insights from CAMELS simulations and ACT+DES data

Abstract

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. We investigate how the observable properties of group-scale halos can constrain feedback's impact on the matter distribution using Cosmology and Astrophysics with MachinE Learning Simulations (CAMELS). Extending the results of previous work to smaller halo masses and higher wavenumber, k, we find that the baryon fraction in halos contains significant information about the impact of feedback on the matter power spectrum. We explore how the thermal Sunyaev Zel'dovich (tSZ) signal from group-scale halos contains 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 feedback effects on the power spectrum at k ∼ 5 h/Mpc. We show 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 that we introduce here. Finally, we investigate the impact of feedback on the matter bispectrum, finding that tSZ observables are highly informative in this case.

Deciphering baryonic feedback with galaxy clusters

“…[37] has considered the prospect of using the ⟨Y |M ⟩ of low mass halos to constrain the modulation of matter power spectra. But, we note that those studies are dominated by halos with a mass lower than our mass limit.…”

“…We consider 9 and 8 Y500c bins for Magneticum and illustris-TNG respectively. The number of clusters in each bin is[138,74,54,37,20,17,5,2,2] and[42,23,24,9,7,2,1,2] respectively. For the Magneticum case, we have checked that reducing to 5 bins does not change the result.…”