Cosmic variance limits the accuracy of cosmological N-body simulations,
introducing bias in statistics such as the power spectrum, halo mass function,
or the cosmic shear. We provide new methods to measure and reduce the effect of
cosmic variance in existing and new simulations. We run pairs of simulations
using phase shifted initial conditions with matching amplitudes. We set the
initial amplitudes of the Fourier modes to ensure that the average power
spectrum of the pair is equal to the cosmic mean power spectrum from linear
theory. The average power spectrum of a pair of such simulations remains
consistent with the estimated non-linear spectra of the state-of-the-art
methods even at late times. We also show that the effect of cosmic variance on
any analysis involving a cosmological simulation can be estimated by using the
complementary pair of the original simulation. To demonstrate the effectiveness
of our novel technique, we simulated a complementary pair of the original
Millennium run and quantified the degree to which cosmic variance affected its
the power spectrum. The average power spectrum of the original and
complementary Millennium simulation was able to directly resolve the baryon
acoustic oscillation features.
%0 Generic
%1 racz2022complementary
%A Rácz, Gábor
%A Kiessling, Alina
%A Csabai, István
%A Szapudi, István
%D 2022
%K library
%T Complementary Cosmological Simulations
%U http://arxiv.org/abs/2210.15077
%X Cosmic variance limits the accuracy of cosmological N-body simulations,
introducing bias in statistics such as the power spectrum, halo mass function,
or the cosmic shear. We provide new methods to measure and reduce the effect of
cosmic variance in existing and new simulations. We run pairs of simulations
using phase shifted initial conditions with matching amplitudes. We set the
initial amplitudes of the Fourier modes to ensure that the average power
spectrum of the pair is equal to the cosmic mean power spectrum from linear
theory. The average power spectrum of a pair of such simulations remains
consistent with the estimated non-linear spectra of the state-of-the-art
methods even at late times. We also show that the effect of cosmic variance on
any analysis involving a cosmological simulation can be estimated by using the
complementary pair of the original simulation. To demonstrate the effectiveness
of our novel technique, we simulated a complementary pair of the original
Millennium run and quantified the degree to which cosmic variance affected its
the power spectrum. The average power spectrum of the original and
complementary Millennium simulation was able to directly resolve the baryon
acoustic oscillation features.
@misc{racz2022complementary,
abstract = {Cosmic variance limits the accuracy of cosmological N-body simulations,
introducing bias in statistics such as the power spectrum, halo mass function,
or the cosmic shear. We provide new methods to measure and reduce the effect of
cosmic variance in existing and new simulations. We run pairs of simulations
using phase shifted initial conditions with matching amplitudes. We set the
initial amplitudes of the Fourier modes to ensure that the average power
spectrum of the pair is equal to the cosmic mean power spectrum from linear
theory. The average power spectrum of a pair of such simulations remains
consistent with the estimated non-linear spectra of the state-of-the-art
methods even at late times. We also show that the effect of cosmic variance on
any analysis involving a cosmological simulation can be estimated by using the
complementary pair of the original simulation. To demonstrate the effectiveness
of our novel technique, we simulated a complementary pair of the original
Millennium run and quantified the degree to which cosmic variance affected its
the power spectrum. The average power spectrum of the original and
complementary Millennium simulation was able to directly resolve the baryon
acoustic oscillation features.},
added-at = {2022-10-28T14:17:40.000+0200},
author = {Rácz, Gábor and Kiessling, Alina and Csabai, István and Szapudi, István},
biburl = {https://www.bibsonomy.org/bibtex/2c81ea7e91aaa5a095d2836c34db2ad39/gpkulkarni},
description = {Complementary Cosmological Simulations},
interhash = {0cc91250e59690601bec68ad4cea0142},
intrahash = {c81ea7e91aaa5a095d2836c34db2ad39},
keywords = {library},
note = {cite arxiv:2210.15077Comment: 7 pages, 4 figures, submitted to Astronomy & Astrophysics (A&A)},
timestamp = {2022-10-28T14:17:40.000+0200},
title = {Complementary Cosmological Simulations},
url = {http://arxiv.org/abs/2210.15077},
year = 2022
}