Imprint of DES superstructures on the cosmic microwave background

Abstract

Small temperature anisotropies in the cosmic microwave background (CMB) can be sourced by density perturbations via the late-time integrated Sachs-Wolfe (ISW) 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 (DES) in a different footprint, and using a different superstructure 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 Delta T-f approximate to -5.0 +/- 3.7 mu K and a hot imprint of superclusters Delta T-f approximate to 5.1 +/- 3.2 mu K; this is similar to 1.2 sigma higher than the expected vertical bar Delta T-f vertical bar approximate to 0.6 mu K imprint of such superstructures in Lambda cold dark matter (Lambda CDM). If we instead use an a posteriori selected filter size (R/R-v = 0.6), we can find a temperature decrement as large as Delta T-f approximate to -9.8 +/- 4.7 mu K for voids, which is similar to 2 sigma above Lambda CDM expectations and is comparable to previous measurements made using Sloan Digital Sky Survey superstructure data.