New fitting formula for cosmic non-linear density distribution
Abstract
We have measured the probability distribution function (PDF) of cosmic matter density field from a suite of N-body simulations. We propose the generalized normal distribution of version 2 (Nv2) as an alternative fitting formula to the well-known log-normal distribution. We find that Nv2 provides significantly better fit than the log-normal distribution for all smoothing radii (2, 5, 10, 25 [Mpc/h]) that we studied. The improvement is substantial in the underdense regions. The development of non- Gaissianities in the cosmic matter density field is captured by continuous evolution of the skewness and shifts parameters of the Nv2 distribution. We present the redshift evolution of these parameters for aforementioned smoothing radii and various background cosmology models. All the PDFs measured from large and high-resolution N-body simulations that we use in this study can be obtained from a Web site at https://astro.kias.re.kr/jhshin.
Keywords
Cite
@article{arxiv.1705.06863,
title = {New fitting formula for cosmic non-linear density distribution},
author = {Jihye Shin and Juhan Kim and Christophe Pichon and Donghui Jeong and Changbom Park},
journal= {arXiv preprint arXiv:1705.06863},
year = {2017}
}
Comments
Accepted for publication in ApJ