Transients from Zel'dovich initial conditions

Abstract

We investigate the error implied by the use of the Zel'dovich approximation to set up the initial conditions at a finite redshift zi in numerical simulations. Using a steepest-descent method developed in a previous work we derive the probability distribution P(delta_R) of the density contrast in the quasi-linear regime. This also provides its dependence on the redshift zi at which the simulation is started. Thus, we find that the discrepancy with the exact pdf (defined by the limit zi->infinity) is negligible after the scale factor has grown by a factor a/a_i>5, for scales which were initially within the linear regime with sigma_i>0.1. This shows that the use of the Zel'dovich approximation to implement the initial conditions is sufficient for practical purposes since these are not very severe constraints.

6 pages, final version published in A&A

References in corpus (3)

• Dynamics of gravitational clustering II. Steepest-descent method for the quasi-linear regime
• Dynamics of gravitational clustering IV. The probability distribution of rare events
• Dynamics of gravitational clustering III. The quasi-linear regime for some non-Gaussian initial conditions

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• Cosmological Vlasov-Poisson equations for dark matter: Recent developments and connections to selected plasma problems
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• Transients from initial conditions based on Lagrangian perturbation theory in N-body simulations
• Transients from initial conditions based on Lagrangian perturbation theory in $N$-body simulations II: the effect of the transverse mode
• Transients from Initial Conditions Based on Lagrangian Perturbation Theory in $N$-body Simulations III: The Case of GADGET-2 Code