1994/12/20 by T. Buchert, Thomas Buchert, A. L. Melott +6
Physics and Astronomy · #Astronomy and Astrophysical Research #Astrophysics (astro-ph) #Cosmology and Gravitation Theories #FOS: Physical sciences #Galaxies: Formation, Evolution, Phenomena #astro-ph
paper · pdf · doi:10.48550/arxiv.astro-ph/9412075
5 pages + cover sheet uuencoded postscript, no figures. For figures and a more detailed dicscussion, see astro-ph/9404018, whose full body and over 10Mbytes of figures are avialable at ftp://ibm-3.mpa-garching.mpg.de/pub/aow/9404018
arxiv created 1994/12/20 · openalex publication_date 1994/12/20 · arxiv updated 2009/12/01 · openalex created_date 2025/10/24 · openalex updated_date 2026/07/28
Approximations to the exact solutions for gravitational instability in the\nexpanding Universe are extremely useful for understanding the evolution of\nlarge--scale structure. We report on a series of tests of Newtonian Lagrangian\nperturbation schemes using N--body simulations for various power--spectra with\nscale--independent indices in the range -3 to +1. The models have been\nevolved deeply into the non--linear regime of structure formation in order to\nprobe the dynamical and statistical performance of the Lagrangian perturbation\nschemes (whose first--order solution contains as a subset the celebrated\n``Zel'dovich--approximation'', hereafter ZA). These tests reveal properties of\nthe approximations at stages beyond the obvious validity of perturbation\ntheory. Recently, another series of tests of different analytical and\nsemi--numerical approximations for large--scale structure was conducted with\nthe result that ZA displays the best dynamical performance in comparison with\nthe N--body simulations, if the initial data were smoothed before evolving the\nmodel, i.e., a truncated form of ZA (TZA). We show in this contribution that\nthe excellent performance of TZA can be further improved by going to second\norder in the Lagrangian perturbation approach. The truncated second--order\nLagrangian scheme provides a useful improvement over TZA especially for\nnegative power indices, which suggests it will be very useful for modelling\nstandard scenarios such as ``Cold--'', ``Hot--'' and ``Mixed--Dark--Matter''.\n