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Imprint of DES super-structures on the Cosmic Microwave Background
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Abstract
Small temperature anisotropies in the Cosmic Microwave Background can be sourced by density perturbations via the late-time integrated Sachs-Wolfe effect. Large voids and superclusters are excellent environments to make a localized measurement of this tiny imprint. In some cases excess signals have been reported. We probed these claims with an independent data set, using the first year data of the Dark Energy Survey in a different footprint, and using a different super-structure finding strategy. We identified 52 large voids and 102 superclusters at redshifts 0.2<z<0.65. We used the Jubilee simulation to a priori evaluate the optimal ISW measurement configuration for our compensated top-hat filtering technique, and then performed a stacking measurement of the CMB temperature field based on the DES data. For optimal configurations, we detected a cumulative cold imprint of voids with ΔTf≈−5.0±3.7 μK and a hot imprint of superclusters ΔTf≈5.1±3.2 μK ; this is ∼1.2σ higher than the expected ∣ΔTf∣≈0.6 μK imprint of such super-structures in ΛCDM. If we instead use an a posteriori selected filter size (R/Rv=0.6), we can find a temperature decrement as large as ΔTf≈−9.8±4.7 μK for voids, which is ∼2σ above ΛCDM expectations and is comparable to previous measurements made using SDSS super-structure data