On fast generation of cosmological random fields

J. Carron, M. Wolk, I. Szapudi

Research output: Contribution to journalArticle

7 Citations (Scopus)

Abstract

The statistical translation invariance of cosmological random fields is broken by a finite survey boundary, correlating the observable Fourier modes. Standard methods for generating Gaussian fields either neglect these correlations, or are costly, or both. Here, we report on a fast and exact simulation method applicable to a wide class of two-point statistics that requires the simulation of a periodic grid of only twice the survey side with fast Fourier transforms. Supersurvey modes, dominating the covariance of power spectra beyond linear scales in galaxy surveys and causing the correlation of large and small scales, 'beat coupling', or 'super-sample' covariance, are precisely accounted for in non-linear transformations of the Gaussian field. As an application, we simulate the CFHTLS (Canada-France-Hawaii Telescope Large Survey) ~7° × 7° W1 galaxy density field, modelled as a Poisson sampling of a lognormal density field. We show that our simulations produce power spectra, A*-power spectra, counts-in-cells probability distributions as well as covariances perfectly consistent with the data. In addition, our technique reproduces the information plateau beyond linear scales as observed previously in Sloan Digital Sky Survey galaxy catalogues and in N-body simulations. Our method is thus an efficient yet powerful simulation and prediction tool for galaxy survey data and covariances.

Original languageEnglish
Pages (from-to)994-1000
Number of pages7
JournalMonthly Notices of the Royal Astronomical Society
Volume444
Issue number1
DOIs
Publication statusPublished - Jul 26 2014

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galaxies
power spectra
simulation
France
Canada
catalogs
invariance
plateaus
synchronism
Fourier transform
sampling
grids
statistics
telescopes
plateau
predictions
cells
prediction
method

Keywords

  • Cosmology: observations
  • Large scale structure of universe
  • Methods: numerical

ASJC Scopus subject areas

  • Space and Planetary Science
  • Astronomy and Astrophysics

Cite this

On fast generation of cosmological random fields. / Carron, J.; Wolk, M.; Szapudi, I.

In: Monthly Notices of the Royal Astronomical Society, Vol. 444, No. 1, 26.07.2014, p. 994-1000.

Research output: Contribution to journalArticle

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