Constraining baryonic physics with DES Y1 and Planck data: Combining galaxy clustering, weak lensing, and CMB lensing

We constrain cosmology and baryonic feedback scenarios with a joint analysis of weak lensing, galaxy clustering, cosmic microwave background (CMB) lensing, and their cross-correlations (so-called 6x2) using data from the Dark Energy Survey (DES) Y1 and the Planck satellite mission. Noteworthy features of our 6x2 pipeline are: We extend CMB lensing cross-correlation measurements to a band surrounding the DES Y1 footprint (around 25% gain in pairs), and we develop analytic covariance capabilities that account for different footprints and all cross-terms in the 6x2 analysis. We also measure the DES Y1 cosmic shear two-point correlation function (2PCF) down to 0.' 25, but find that going below 2.' 5 does not increase cosmological information due to shape noise. We model baryonic physics uncertainties via the amplitude of principal components (PCs) derived from a set of hydrosimulations. Given our statistical uncertainties, varying the first PC amplitude Q(1) is sufficient to model small scale cosmic shear 2PCF. For DES Y1+Planck 6x2 we find S-8=0.799 +/- 0.016, comparable to the 5x2 result of DES Y3+SPT/Planck S-8=0.773 +/- 0.016. Combined with our most informative cosmology priors-baryon acoustic oscillation, big bang nucleosynthesis, type Ia supernovae, and Planck 2018 EE+lowE, we measure S-8=0.817 +/- 0.011. Regarding baryonic physics constraints, our 6x2 analysis finds Q(1)=2.8 +/- 1.8. Combined with the aforementioned priors, it improves the constraint to Q(1)=3.5 +/- 1.3. For comparison, the strongest feedback scenario considered in this paper, the cosmo-OWLS AGN (Delta T-heat=10(8.7) K), corresponds to Q(1)=5.84.