Subaru Hyper Suprime-Cam excavates colossal over- and under-dense structures over 360 deg2 out to z=1

Abstract

Subaru Strategic Program with the Hyper-Suprime Cam (HSC-SSP) has proven to be successful with its extremely-wide area coverage in past years. Taking advantages of this feature, we report initial results from exploration and research of expansive over-and under-dense structures at 𝑧 = 0.3 -1 based on the second Public Data Release where optical 5-band photometric data for ∼ eight million sources with 𝑖 < 23 mag are available over ∼ 360 square degrees. We not only confirm known superclusters but also find candidates of titanic over-and under-dense regions out to 𝑧 = 1. The mock data analysis suggests that the density peaks would involve one or more massive dark matter haloes (> 10 14 M ) of the redshift, and the density troughs tend to be empty of massive haloes over > 10 comoving Mpc. Besides, the density peaks and troughs at 𝑧 0.6 are in part identified as positive and negative weak lensing signals respectively, in mean tangential shear profiles, showing a good agreement with those inferred from the full-sky weak lensing simulation. The coming extensive spectroscopic surveys will be able to resolve these colossal structures in three-dimensional space. The number density information over the entire survey field is available as grid-point data on the website of the HSC-SSP data release (https://hsc.mtk.nao.ac.jp/ssp/data-release/).

Dark Energy Survey Year 3 results: curved-sky weak lensing mass map reconstruction

“…Nevertheless, such a supervoid is comparable to the largest known underdensities in the local Universe, and these objects are of great interest in cosmology (see e.g. Shimakawa et al 2021). Their integrated Sachs-Wolfe imprint has already been studied using DES Y3 data to probe dark energy (for details see Kovács et al 2019).…”