Quantifying baryonic feedback on the weak lensing 3×2 and 4×3 point correlation functions using HACC simulations

We investigate the impact of baryonic feedback on simulated photometric clustering and weak lensing data measured with two-point (2pt) and three-point (3pt) correlation functions. We baryonify high-resolution simulations to probe the impact of baryons down to sub-arcminute scales, varying the two model parameters with the largest impact on our probes: M_c, which governs the amount of gas expelled beyond the halo virial radius, and θ_ej, which encodes the maximal ejection radius. We create lensing maps and catalogues assuming survey properties of the upcoming Year-1 data release from the Rubin Observatory's LSST Dark Energy Science Collaboration (DESC) and investigate the impact of baryons on the observed correlations, including the galaxy-galaxy-shear (ggG) and the galaxy-shear-shear (gGG) correlation functions, which are measured with the new TreeCorr capability. Focusing on the equilateral configuration, we find that small scales are more heavily affected by baryonic effects than the corresponding 2pt functions, approximately by a factor of 3/2, as expected from the field order. The 3pt clustering term, ggg, is significantly affected at scales smaller than about 4 arcmin; this occurs at 10 arcmin for the gGG terms, at 40 arcmin for the gGG terms,  and at about a degree for the shear 3pt function (GGG). This is consistent with the scales and redshift probed by these different statistics, and the amount of projection. The 4×3pt statistics can therefore be used at large scales to robustly probe cosmological parameters, while the increased sensitivity to baryonic physics at smaller scales can help constraining the BCM parameters and provide useful prior information.