We investigate the accuracy of the frozen-flow approximation (FFA), recently proposed by Matarrese et al., for tracing of the non-linear evolution of cosmological density fluctuations under gravitational instability. We compare a number of statistics between results of the FFA and N-body simulations, including those used by Melon, Pellman & Shandarin to test the Zel'dovich approximation. The FFA performs reasonably well in a statistical sense (for example, in reproducing the counts-in-cells distribution) at small scales, but it does poorly in the cross-correlation with N-body simulations, which means that it is generally not moving mass to the right place, especially in models with high small-scale power.
Testing the Frozen Flow Approximation
LUCCHIN, FRANCESCO;MATARRESE, SABINO;MOSCARDINI, LAURO
1994
Abstract
We investigate the accuracy of the frozen-flow approximation (FFA), recently proposed by Matarrese et al., for tracing of the non-linear evolution of cosmological density fluctuations under gravitational instability. We compare a number of statistics between results of the FFA and N-body simulations, including those used by Melon, Pellman & Shandarin to test the Zel'dovich approximation. The FFA performs reasonably well in a statistical sense (for example, in reproducing the counts-in-cells distribution) at small scales, but it does poorly in the cross-correlation with N-body simulations, which means that it is generally not moving mass to the right place, especially in models with high small-scale power.
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