Results are reported on N-body simulations of the large-scale structure of the Universe starting from non-Gaussian initial conditions in a Cold Dark Matter cosmogony. Three multiplicative models are considered where the peculiar gravitational potential is obtained by performing a nonlinear transformation on a Gaussian random field: while keeping the standard form for the initial power spectrum, this procedure provides highly nonrandom phases. The resulting distributions in space and velocity are analyzed by different statistical tests and compared with the evolution of a standard Gaussian model with the same initial amplitude. It is found that both the clustering dynamics and the present texture are mostly sensitive to the sign of the initial skewness of mass fluctuations. In particular, models characterized by a substantial predominance of primordial underdense regions (negative skewness) evolve toward a cellular structure with large correlation length and enhanced peculiar motions. The results suggest that the Cold Dark Matter scenario can succeed in reproducing structures, on large scales if the random-phase hypothesis is abandoned.

Non-Gaussian Initial Conditions in Cosmological N-body Simulations: II. Cold Dark Matter Models

MOSCARDINI, LAURO;MATARRESE, SABINO;LUCCHIN, FRANCESCO;
1991

Abstract

Results are reported on N-body simulations of the large-scale structure of the Universe starting from non-Gaussian initial conditions in a Cold Dark Matter cosmogony. Three multiplicative models are considered where the peculiar gravitational potential is obtained by performing a nonlinear transformation on a Gaussian random field: while keeping the standard form for the initial power spectrum, this procedure provides highly nonrandom phases. The resulting distributions in space and velocity are analyzed by different statistical tests and compared with the evolution of a standard Gaussian model with the same initial amplitude. It is found that both the clustering dynamics and the present texture are mostly sensitive to the sign of the initial skewness of mass fluctuations. In particular, models characterized by a substantial predominance of primordial underdense regions (negative skewness) evolve toward a cellular structure with large correlation length and enhanced peculiar motions. The results suggest that the Cold Dark Matter scenario can succeed in reproducing structures, on large scales if the random-phase hypothesis is abandoned.
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Utilizza questo identificativo per citare o creare un link a questo documento: http://hdl.handle.net/11577/135451
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