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 AISW = ΔTdata/ΔTtheory = 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 deg2 footprint of the Dark Energy Survey at 0.2 < z < 0.9 to probe these anomalous claims. We found an excess imprinted profile with AISW ≈ 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 AISW ≈ 5.2 ± 1.6 amplitude. The tension with ΛCDM predictions is equivalent to 2.6σ and remains unexplained.