Forecasts for WEAVE-QSO: 3D clustering of critical points with Lyman-alpha tomography
Monthly Notices of the Royal Astronomical Society Oxford University Press 514:1 (2022) 1359-1385
Authors:
Katarina Kraljic, Clotilde Laigle, Christophe Pichon, Sebsatien Peirani, Sandrine Codis, Junsup Shim, Dmitri Pogosyan, Corentin Cadiou, Stephane Arnouts, Matthew Pieri, Sean Morrison, Ignasi Pérez Ràfols, Jose Oñorbe, Vid Irsic, Gavin Dalton
Abstract:
The upcoming WEAVE-QSO survey will target a high density of quasars over a large area,
enabling the reconstruction of the 3D density field through Lyman-훼 tomography over unprecedented volumes smoothed on intermediate cosmological scales (≈ 16 Mpc/h). We produce mocks of the Lyman-훼 forest using LyMAS, and reconstruct the 3D density field between
sightlines through Wiener filtering in a configuration compatible with the future WEAVE-QSO
observations. The fidelity of the reconstruction is assessed by measuring one- and two-point
statistics from the distribution of critical points in the cosmic web. In addition, initial Lagrangian statistics are predicted from first principles, and measurements of the connectivity of
the cosmic web are performed. The reconstruction captures well the expected features in the
auto- and cross-correlations of the critical points. This remains true after a realistic noise is
added to the synthetic spectra, even though sparsity of sightlines introduces systematics, especially in the cross-correlations of points with mixed signature. Specifically, the most striking
clustering features involving filaments and walls could be measured with up to 4 sigma
of significance with a WEAVE-QSO-like survey. Moreover, the connectivity of each peak
identified in the reconstructed field is globally consistent with its counterpart in the original
field, indicating that the reconstruction preserves the geometry of the density field not only
statistically, but also locally. Hence the critical points relative positions within the tomographic
reconstruction could be used as standard rulers for dark energy by WEAVE-QSO and similar
surveys.