TY - JOUR

T1 - Non-Gaussianity of the density distribution in accelerating universes

AU - Tatekawa, Takayuki

AU - Mizuno, Shuntaro

PY - 2006/2/1

Y1 - 2006/2/1

N2 - According to recent observations, the existence of dark energy has been considered. Even though we have obtained the constraint of the equation of the state for dark energy (p ≤ wρ) as -1 ≤ w ≤ -0.78 by combining WMAP data with other astronomical data, in order to pin down w, it is necessary to use other independent observational tools. For this purpose, we consider the w dependence of the non-Gaussianity of the density distribution generated by nonlinear dynamics. To extract the non-Gaussianity, we follow a semi-analytic approach based on Lagrangian linear perturbation theory, which provides an accurate value for the quasi-nonlinear region. From our results, the difference of the non-Gaussianity between w ≤ -1 and -0.5 is about 4%, while that between w ≤ -1 and -0.8 is about 0.9%. For the highly non-linear region, we estimate the difference by combining this perturbative approach with N-body simulation executed for our previous paper. From this, we can expect the difference to be more enhanced in the low-z region, which suggests that the non-Gaussianity of the density distribution potentially plays an important role for extracting information on dark energy.

AB - According to recent observations, the existence of dark energy has been considered. Even though we have obtained the constraint of the equation of the state for dark energy (p ≤ wρ) as -1 ≤ w ≤ -0.78 by combining WMAP data with other astronomical data, in order to pin down w, it is necessary to use other independent observational tools. For this purpose, we consider the w dependence of the non-Gaussianity of the density distribution generated by nonlinear dynamics. To extract the non-Gaussianity, we follow a semi-analytic approach based on Lagrangian linear perturbation theory, which provides an accurate value for the quasi-nonlinear region. From our results, the difference of the non-Gaussianity between w ≤ -1 and -0.5 is about 4%, while that between w ≤ -1 and -0.8 is about 0.9%. For the highly non-linear region, we estimate the difference by combining this perturbative approach with N-body simulation executed for our previous paper. From this, we can expect the difference to be more enhanced in the low-z region, which suggests that the non-Gaussianity of the density distribution potentially plays an important role for extracting information on dark energy.

KW - Cosmic flows

KW - Cosmological perturbation theory

KW - Dark energy theory

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U2 - 10.1088/1475-7516/2006/02/006

DO - 10.1088/1475-7516/2006/02/006

M3 - Article

AN - SCOPUS:84856396083

JO - Journal of Cosmology and Astroparticle Physics

JF - Journal of Cosmology and Astroparticle Physics

SN - 1475-7516

IS - 2

M1 - 006

ER -