More out of less: an excess integrated Sachs-Wolfe signal from supervoids mapped out by the Dark Energy Survey

Abstract

The largest structures in the cosmic web probe the dynamical nature of dark energy through their integrated Sachs-Wolfe imprints. In the strength of the signal, typical cosmic voids have shown good consistency with expectation A ISW = ∆T data /∆T theory = 1, given the substantial cosmic variance. Discordantly, large-scale hills in the gravitational potential, or supervoids, have shown excess signals. In this study, we mapped out 87 new supervoids in the total 5000 deg 2 footprint of the Dark Energy Survey at 0.2 < z < 0.9 to probe these anomalous claims. We found an excess imprinted profile with A ISW ≈ 4.1 ± 2.0 amplitude. The combination with independent BOSS data reveals an ISW imprint of supervoids at the 3.3σ significance level with an enhanced A ISW ≈ 5.2 ± 1.6 amplitude. The tension with ΛCDM predictions is equivalent to 2.6σ and remains unexplained.