Abstract
Cross-correlations of galaxy positions and galaxy shears with maps of
gravitational lensing of the cosmic microwave background (CMB) are sensitive to
the distribution of large-scale structure in the Universe. Such
cross-correlations are also expected to be immune to some of the systematic
effects that complicate correlation measurements internal to galaxy surveys. We
present measurements and modeling of the cross-correlations between galaxy
positions and galaxy lensing measured in the first three years of data from the
Dark Energy Survey with CMB lensing maps derived from a combination of data
from the 2500 deg$^2$ SPT-SZ survey conducted with the South Pole Telescope and
full-sky data from the Planck satellite. The CMB lensing maps used in this
analysis have been constructed in a way that minimizes biases from the thermal
Sunyaev Zel'dovich effect, making them well suited for cross-correlation
studies. The total signal-to-noise of the cross-correlation measurements is
23.9 (25.7) when using a choice of angular scales optimized for a linear
(nonlinear) galaxy bias model. We use the cross-correlation measurements to
obtain constraints on cosmological parameters. For our fiducial galaxy sample,
which consist of four bins of magnitude-selected galaxies, we find constraints
of $Ømega_m = 0.27^+0.03_-0.05$ and $S_8 \sigma_8
Ømega_m/0.3= 0.74^+0.03_-0.04$ ($Ømega_m =
0.25^+0.03_-0.04$ and $S_8 = 0.73^+0.04_-0.03$) when assuming linear
(nonlinear) galaxy bias in our modeling. Considering only the cross-correlation
of galaxy shear with CMB lensing, we find $Ømega_m= 0.27^+0.04_-0.06$
and $S_8= 0.74^+0.03_-0.04$. Our constraints on $S_8$ are consistent with
recent cosmic shear measurements, but lower than the values preferred by
primary CMB measurements from Planck.
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