Skip to main content
Open Access Publications from the University of California


  • Author(s): Lee, KG
  • White, M
  • et al.

Published Web Location
No data is associated with this publication.

© 2016. The American Astronomical Society. All rights reserved. Studies of cosmological objects should take into account their positions within the cosmic web of large-scale structure. Unfortunately, the cosmic web has only been extensively mapped at low redshifts (z < 1), using galaxy redshifts as tracers of the underlying density field. At z > 1, the required galaxy densities are inaccessible for the foreseeable future, but 3D reconstructions of Lya forest absorption in closely separated background QSOs and star-forming galaxies already offer a detailed window into z ∼ 2-3 large-scale structure. We quantify the utility of such maps for studying the cosmic web by using realistic z=2.5 Lya forest simulations matched to observational properties of upcoming surveys. A deformation tensor-based analysis is used to classify voids, sheets, filaments, and nodes in the flux, which are compared to those determined from the underlying dark matter (DM) field. We find an extremely good correspondence, with 70% of the volume in the flux maps correctly classified relative to the DM web, and 99% classified to within one eigenvalue. This compares favorably to the performance of galaxybased classifiers with even the highest galaxy densities from low-redshift surveys. We find that narrow survey geometries can degrade the recovery of the cosmic web unless the survey is ≳60 Mpc h-1or ≳1 deg on the sky. We also examine halo abundances as a function of the cosmic web, and find a clear dependence as a function of flux overdensity, but little explicit dependence on the cosmic web. These methods will provide a new window on cosmological environments of galaxies at this very special time in galaxy formation, "high noon," and on overall properties of cosmological structures at this epoch.

Many UC-authored scholarly publications are freely available on this site because of the UC Academic Senate's Open Access Policy. Let us know how this access is important for you.

Item not freely available? Link broken?
Report a problem accessing this item