Systematic Effects on the Genus Topology of Large Scale Structure of the Universe

Abstract

Large-scale structure of the universe is a useful cosmological probe of the primordial non-Gaussianity and the expansion history of the universe because its topology does not change with time in the linear regime in the standard paradigm of structure formation. However, when the topology of iso-density contour surfaces is measured from an observational data, many systematic effects are introduced due to the finite size of pixels used to define the density field, non-linear gravitational evolution, redshift-space distortion, shot noise (discrete sampling), and bias in the distribution of the density field tracers. We study the various systematic effects on the genus curve to a great accuracy by using the Horizon Run 2 simulation of a ΛCDM cosmology. We numerically measure the genus curve from the gravitationally evolved matter and dark matter halo density fields. It is found that all the non-Gaussian deviations due to the systematic effects can be modeled by using a few low-order Hermite polynomials from H0 to H4. We compare our results with the analytic theories whenever possible, and find many new terms in the Hermite series that are making significant contributions to the non-Gaussian deviations. In particular, it is found that the amplitude drop of the genus curve due to the non-linear gravitational evolution can be accurately modeled by two terms H0 and H2 with coefficients both proportional to σ_0^2, the mean-square density fluctuation.

arXiv comment44 pages, 13 figures, 8 tables, Accepted for publication in ApJS

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Cited by in corpus (11)

• Horizon Run 4 Simulation: Coupled Evolution of Galaxies and Large-scale Structures of the Universe
• Minkowski Functionals of SDSS-III BOSS : Hints of Possible Anisotropy in the Density Field?
• Probing massive neutrinos with the Minkowski functionals of large-scale structure
• Probing massive neutrinos with the Minkowski functionals of the galaxy distribution
• Cosmological Parameter Estimation Using the Genus Amplitude - Application to Mock Galaxy Catalogs
• Cosmological Parameter Estimation from the Two-Dimensional Genus Topology -- Measuring the Shape of the Matter Power Spectrum
• Cosmological Parameter Estimation from the Two-Dimensional Genus Topology -- Measuring the Expansion History using the Genus Amplitude as a Standard Ruler
• Topology of Large-Scale Structures of Galaxies in Two Dimensions - Systematic Effects
• Minkowski Tensors in Redshift Space -- Beyond the Plane Parallel Approximation
• Recovering dark-matter clustering from galaxies with Gaussianization
• Horizon Run 3: Topology as a Standard Ruler