Performance of the Optimized Post-Zel'dovich Approximation for Cold Dark Matter Models in Arbitrary FLRW Cosmologies

Abstract

We investigate the performance of the optimized post-Zel'dovich approximation in three cold dark matter cosmologies. We consider two flat models with Ω0=1 (SCDM) and with Ω0=0.3 (ΛCDM) and an open model with Ω0=0.3 (OCDM). We find that the optimization scheme proposed by Weiss, Gottlober, & Buchert, in which the performance of the Lagrangian perturbation theory was optimized only for the Einstein-de Sitter cosmology, shows excellent performance not only for SCDM model but also for both OCDM and ΛCDM models. This universality of the excellent performance of the optimized post-Zel'dovich approximation is explained by the fact that a relation between the post-Zel'dovich order's growth factor E(a) and Zel'dovich order's one D(a), E(a)/D2(a), is insensitive to the background cosmologies.