Constraining accuracy of the pairwise velocities in $N$-body simulations using scale-free models

Bibliographic Details
Title: Constraining accuracy of the pairwise velocities in $N$-body simulations using scale-free models
Authors: Maleubre, Sara, Eisenstein, Daniel J., Garrison, Lehman H., Joyce, Michael
Publication Year: 2022
Collection: Astrophysics
Subject Terms: Astrophysics - Cosmology and Nongalactic Astrophysics
More Details: We present a continuation of an analysis that aims to quantify resolution of $N$-body simulations by exploiting large (up to $N=4096^3$) simulations of scale-free cosmologies run using Abacus. Here we focus on radial pairwise velocities of the matter field, both by direct estimation and through the cumulative-2PCF (using the pair conservation equation). We find that convergence at the $1\%$ level of the mean relative pairwise velocity can be demonstrated over a range of scales, evolving from a few times the grid spacing at early times to slightly below this scale at late times. We show the analysis of two different box sizes as well as from averaging results from the smaller boxes, and compare the power of the two aforementioned estimators in constraining accuracy at each scale. Down to scales of order of the smoothing parameter, convergence is obtained at $\sim5\%$ precision, and shows a behaviour indicating asymptotic stable clustering. We also infer for LCDM simulations conservative estimates on the evolution of the lower cut-off to resolution (at $1\%$ and $5\%$ precision) as a function of redshift.
Comment: 14 pages, 9 figures, 1 table. Accepted for publication in MNRAS. v2 does NOT overlap with arXiv:2308.00438
Document Type: Working Paper
DOI: 10.1093/mnras/stad2388
Access URL: http://arxiv.org/abs/2211.07607
Accession Number: edsarx.2211.07607
Database: arXiv
More Details
DOI:10.1093/mnras/stad2388