Abstract
ABSTRACT Cosmic voids gravitationally lens the cosmic microwave background (CMB) radiation, resulting in a distinct imprint on degree scales. We use the simulated CMB lensing convergence map from the Marenostrum Institut de Ciencias de l’Espai (MICE) N-body simulation to calibrate our detection strategy for a given void definition and galaxy tracer density. We then identify cosmic voids in Dark Energy Survey (DES) Year 1 data and stack the Planck 2015 lensing convergence map on their locations, probing the consistency of simulated and observed void lensing signals. When fixing the shape of the stacked convergence profile to that calibrated from simulations, we find imprints at the 3σ significance level for various analysis choices. The best measurement strategies based on the MICE calibration process yield S/N ≈ 4 for DES Y1, and the best-fitting amplitude recovered from the data is consistent with expectations from MICE (A ≈ 1). Given these results as well as the agreement between them and N-body simulations, we conclude that the previously reported excess integrated Sachs–Wolfe (ISW) signal associated with cosmic voids in DES Y1 has no counterpart in the Planck CMB lensing map.
Highlights
The standard model of cosmology is based on the assumption that our universe is homogeneous and isotropic at large scales
FOR OBSERVATIONS: Dark Energy Survey (DES) Y1 × PLANCK We measure the stacked imprint of DES Y1 voids with the same methodology and parameters as in the case of the MICE mock
Together with the MICE results, the stacked κ images of the DES Y1 void catalogues are shown in Figures 2 and 3 for 2D and VIDE voids, respectively
Summary
The standard model of cosmology is based on the assumption that our universe is homogeneous and isotropic at large scales. Surrounded by galaxies, galaxy clusters, filaments and walls, cosmic voids are large underdense regions that occupy the majority of space in our Universe. They are the most dark energy dominated regions in the cosmic web, essentially devoid of dark matter and related non-linear effects. Brax (2012) for a review of such models) These screening mechanisms predict that the intrinsic density of high-density regions (such as dark matter halos) and low-density regions (such as cosmic voids as the unscreened regime) will be more and less dense, respectively, than in the general relativity scenario (Martino & Sheth 2009). Measuring the underlying matter profile of these structures appears to be an interesting tool to probe cosmological models (Cautun et al 2018)
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