Crosscorrelation of gravitational lensing from DES Science Verification data with SPT and Planck lensing
Abstract
We measure the crosscorrelation between weak lensing of galaxy images and of the cosmic microwave background (CMB). The effects of gravitational lensing on different sources will be correlated if the lensing is caused by the same mass fluctuations. We use galaxy shape measurements from 139 deg^{2} of the Dark Energy Survey (DES) Science Verification data and overlapping CMB lensing from the South Pole Telescope (SPT) and Planck. The DES source galaxies have a median redshift of z_{med} ∼ 0.7, while the CMB lensing kernel is broad and peaks at z ∼ 2. The resulting crosscorrelation is maximally sensitive to mass fluctuations at z ∼ 0.44. Assuming the Planck 2015 bestfitting cosmology, the amplitude of the DES×SPT crosspower is found to be A_{SPT} = 0.88 ± 0.30 and that from DES×Planck to be A_{Planck} = 0.86 ± 0.39, where A = 1 corresponds to the theoretical prediction. These are consistent with the expected signal and correspond to significances of 2.9σ and 2.2σ, respectively. We demonstrate that our results are robust to a number of important systematic effects including the shear measurement method, estimator choice, photoz uncertainty and CMB lensing systematics. We calculate a value of A = 1.08 ± 0.36 for DES×SPT when we correct the observations with a simple intrinsic alignment model. With three measurements of this crosscorrelation now existing in the literature, there is not yet reliable evidence for any deviation from the expected LCDM level of crosscorrelation. We provide forecasts for the expected signaltonoise ratio of the combination of the fiveyear DES survey and SPT3G.
 Publication:

Monthly Notices of the Royal Astronomical Society
 Pub Date:
 June 2016
 DOI:
 10.1093/mnras/stw570
 arXiv:
 arXiv:1512.04535
 Bibcode:
 2016MNRAS.459...21K
 Keywords:

 gravitational lensing: weak;
 methods: data analysis;
 cosmic background radiation;
 Astrophysics  Cosmology and Nongalactic Astrophysics
 EPrint:
 13 pages, 6 figures