Dark Energy Survey Year 1 Results: Cross-correlation between Dark Energy Survey Y1 galaxy weak lensing and South Pole weak lensing

We cross-correlate galaxy weak lensing measurements from the Dark Energy Survey (DES) year-one data with a cosmic microwave background (CMB) weak lensing map derived from South Pole Telescope (SPT) and Planck data, with an effective overlapping area of 1289 deg 2 . With the combined measurements from four source galaxy redshift bins, we obtain a detection significance of 5 . 8 σ . We fit the amplitude of the correlation functions while fixing the cosmological parameters to a fiducial Λ CDM model, finding A ¼ 0 . 99 (cid:2) 0 . 17 . We additionally use the correlation function measurements to constrain shear calibration bias, obtaining constraints that are consistent with previous DES analyses. Finally, when performing a cosmological analysis under the Λ CDM model, we obtain the marginalized constraints of Ω m ¼ 0 . 261 þ 0 . 070 − 0 . 051 and S 8 ≡ σ 8 ffiffiffiffiffiffiffiffiffiffiffiffiffiffiffi Ω m = 0 . 3 p ¼ 0 . 660 þ 0 . 085 − 0 . 100 . These measurements are used in a companion work that presents cosmological constraints from the joint analysis of two-point functions among galaxies, galaxy shears, and CMB lensing using DES, SPT, and Planck data.