Open AccessNegative skewness of radial pairwise velocity in the quasi‐non‐linear regime: Zel'dovich approximation
Author(s) -
Yoshisato Ayako,
Morikawa Masahiro,
Mouri Hideaki
Publication year - 2003
Publication title -
monthly notices of the royal astronomical society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.058
H-Index - 383
eISSN - 1365-2966
pISSN - 0035-8711
DOI - 10.1046/j.1365-8711.2003.06760.x
Subject(s) - physics , skewness , statistical physics , galaxy , cluster analysis , pairwise comparison , astrophysics , statistics , mathematics
According to N ‐body numerical simulations, the radial pairwise velocities of galaxies have negative skewness in the quasi‐non‐linear regime. To understand its origin, we calculate the probability distribution function of the radial pairwise velocity using the Zel'dovich approximation, i.e. an analytical approximation for gravitational clustering. The calculated probability distribution function is in good agreement with the result of N ‐body simulations. Thus, the negative skewness originates in relative motions of galaxies in the clustering process that the infall dominates over the expansion.