The effect of primordial non-Gaussianity on the topology of large-scale structure

Hikage, C, Coles, P, Grossi, M, Moscardini, L, Dolag, K, Branchini, E and Matarrese, S (2008) The effect of primordial non-Gaussianity on the topology of large-scale structure. Monthly Notices of the Royal Astronomical Society, 385 (3). pp. 1613-1620. ISSN 0035-8711

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We study the effect of primordial non-Gaussianity on the development of large-scale cosmic structure using high-resolution N-body simulations. In particular, we focus on the topological properties of the `cosmic web', quantitatively characterized by the Minkowski functionals (MFs), for models with quadratic non-linearities with different values of the usual non-Gaussianity parameter fNL. In the weakly non-linear regime (the amplitude of mass density fluctuations σ0 < 0.1), we find that analytic formulae derived from perturbation theory agree with the numerical results within a few per cent of the amplitude of each MF when |fNL| < 1000. In the non-linear regime, the detailed behaviour of the MFs as functions of threshold density deviates more strongly from the analytical curves, while the overall amplitude of the primordial non-Gaussian effect remains comparable to the perturbative prediction. When smaller-scale information is included, the influence of primordial non-Gaussianity becomes increasingly significant statistically due to decreasing sample variance. We find that the effect of the primordial non-Gaussianity with |fNL| = 50 is comparable to the sample variance of mass density fields with a volume of 0.125(h-1 Gpc)3 when they are smoothed by Gaussian filter at a scale of 5h-1Mpc. The detectability of this effect in actual galaxy surveys will strongly depend on residual uncertainties in cosmological parameters and galaxy biasing.

Item Type: Article
Keywords: methods: analytical , methods: N-body simulations , methods: statistical , early Universe , large-scale structure of Universe
Schools and Departments: School of Mathematical and Physical Sciences > Physics and Astronomy
Subjects: Q Science > QB Astronomy > QB0980 Cosmogony. Cosmology
Depositing User: Peter Coles
Date Deposited: 29 Apr 2013 07:11
Last Modified: 07 Mar 2017 10:31

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