1995/11/26 by Ivar Suisalu, E. Saar, Suisalu, Ivar +2
Physics and Astronomy · #Astronomy and Astrophysical Research #Astrophysics (astro-ph) #Cosmology and Gravitation Theories #FOS: Physical sciences #Stellar, planetary, and galactic studies #astro-ph
paper · pdf · doi:10.48550/arxiv.astro-ph/9511120
10 pages, LaTeX (mn.sty, epsf.sty), 16 PS figures, submitted to MN June 1995
arxiv created 1995/11/26 · openalex publication_date 1995/11/26 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
We study the accumulation of errors in cosmological N-body algorithms that are caused by representing the continuous distribution of matter by massive particles, comparing the PPPM and Adaptive Multigrid codes. We use for this a new measure of two-body relaxation suitable for nonstationary gravitating systems. This measure is based on accumulated deflection angles of particle orbits and it does not saturate during evolution. We have found that the role of gravitational collisions in standard PPPM-models is rather high, and in order to avoid collision effects we recommend to use large comoving softening parameters epsilon>=1.0 (in grid units).