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

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, 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 percent of the amplitude of each MF when |fNL | < 1000. In the non-linear regime, the detailed behavior 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