2004/10/31 by J. S. Bagla, S. Ray, Suryadeep Ray · 3 citations
Physics and Astronomy · #Astronomy and Astrophysical Research #Cosmology and Gravitation Theories #Galaxies: Formation, Evolution, Phenomena #astro-ph
paper · pdf · doi:10.1111/j.1365-2966.2005.08858.x
published as Mon.Not.Roy.Astron.Soc. 358 (2005) 1076-1082 · 7 pages, 8 figures, Accepted for publication in the MNRAS
arxiv created 2005/01/22 · openalex publication_date 2005/03/23 · arxiv updated 2009/12/01 · openalex created_date 2016/06/24 · openalex updated_date 2026/07/28
N-body simulations are a very important tool in the study of the formation of large-scale structures. Much of the progress in understanding the physics of the high-redshift universe and comparison with observations would not have been possible without N-body simulations. Given the importance of this tool, it is essential to understand its limitations, as ignoring the limitations can easily lead to interesting but unreliable results. In this paper we study the limitations arising out of the finite size of the simulation volume. This finite size implies that modes larger than the size of the simulation volume are ignored and a truncated power spectrum is simulated. If the simulation volume is large enough then the mass in collapsed haloes expected from the full power spectrum and from the truncated power spectrum should match. We propose a quantitative measure based on this approach that allows us to compute the minimum box size for an N-body simulation. We find that the required box size for simulations of the ΛCDM model at high redshifts is much larger than is typically used. We can also use this approach to quantify the effect of perturbations at large scales for power-law models and we find that if we fix the scale of non-linearity, the required box size becomes very large as the index becomes small. The appropriate box size computed using this approach is also an appropriate choice for the transition scale when tools like MAP, which add the contribution of the missing power, are used.