Modeling iterative reconstruction and displacement field in the large scale structure

Abstract

The next generation of galaxy surveys like the Dark Energy Spectroscopic Instrument (DESI) and Euclid will provide datasets orders of magnitude larger than anything available to date. Our ability to model nonlinear effects in late time matter perturbations will be a key to unlock the full potential of these datasets, and the area of initial condition reconstruction is attracting growing attention. Iterative reconstruction developed in Ref. [1] is a technique designed to reconstruct the displacement field from the observed galaxy distribution. The nonlinear displacement field and initial linear density field are highly correlated. Therefore, reconstructing the nonlinear displacement field enables us to extract the primordial cosmological information better than from the late time density field at the level of the two-point statistics. This paper will test to what extent the iterative reconstruction can recover the true displacement field and construct a perturbation theory model for the postreconstructed field. We model the iterative reconstruction process with Lagrangian perturbation theory~(LPT) up to third order for dark matter in real space and compare it with $N$-body simulations. We find that the simulated iterative reconstruction does not converge to the nonlinear displacement field, and the discrepancy mainly appears in the shift term, i.e., the term correlated directly with the linear density field. On the contrary, our 3LPT model predicts that the iterative reconstruction should converge to the nonlinear displacement field. We discuss the sources of discrepancy, including numerical noise/artifacts on small scales, and present an ad hoc phenomenological model that improves the agreement.

19 pages, 11 figures, submitted to PRD

References in corpus (20)

• The DESI Experiment Part I: Science,Targeting, and Survey Design
• Wide-Field InfrarRed Survey Telescope-Astrophysics Focused Telescope Assets WFIRST-AFTA 2015 Report
• The Effective Field Theory of Cosmological Large Scale Structures
• Improving Cosmological Distance Measurements by Reconstruction of the Baryon Acoustic Peak
• Resumming Cosmological Perturbations via the Lagrangian Picture: One-loop Results in Real Space and in Redshift Space
• Nonlinear Evolution of Baryon Acoustic Oscillations
• A critical look at cosmological perturbation theory techniques
• Generation of Vorticity and Velocity Dispersion by Orbit Crossing
• Multi-Point Propagators in Cosmological Gravitational Instability
• A Closure Theory for Non-linear Evolution of Cosmological Power Spectra
• Reconstructing Baryon Oscillations: A Lagrangian Theory Perspective
• Dark matter clustering: a simple renormalization group approach
• The Hobby-Eberly Telescope Dark Energy Experiment (HETDEX): Description and Early Pilot Survey Results
• Reconstruction within the Zeldovich approximation
• Third-Order Density Perturbation and One-Loop Power Spectrum in Dark-Energy-Dominated Universe
• Baryonic Acoustic Oscillations via the Renormalization Group
• Third-order Perturbation Theory With Non-linear Pressure
• A coarse grained perturbation theory for the Large Scale Structure, with cosmology and time independence in the UV
• Primordial density and BAO reconstruction
• CosmicRIM : Reconstructing Early Universe by Combining Differentiable Simulations with Recurrent Inference Machines

Cited by in corpus (4)

• Primordial feature constraints from BOSS+eBOSS
• Lagrangian displacement field estimators in cosmology
• Modelling the covariance matrix for the power spectra before and after the BAO reconstruction
• Iterative reconstruction excursions for Baryon Acoustic Oscillations and beyond