Open AccessSimulation of non‐Gaussian cosmic microwave background maps
Author(s) -
Rocha Graca,
Hobson M. P.,
Smith Sarah,
Ferreira Pedro,
Challinor Anthony
Publication year - 2005
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 - 10.1111/j.1365-2966.2005.08552.x
Subject(s) - bispectrum , physics , cosmic microwave background , spectral density , gaussian , statistical physics , probability density function , isotropy , gaussian function , cumulant , gaussian process , computational physics , optics , quantum mechanics , anisotropy , statistics , mathematics
A simple method is presented for the rapid simulation of statistically isotropic non‐Gaussian maps of cosmic microwave background temperature fluctuations with a given power spectrum and analytically calculable bispectrum and higher‐order polyspectra. The n th‐order correlators of the pixel values may also be calculated analytically. The cumulants of the simulated map may be used to obtain an expression for the probability density function of the pixel temperatures. The statistical properties of the simulated map are determined by the univariate non‐Gaussian distribution, from which pixel values are drawn independently in the first stage of the simulation process. We illustrate the method using a non‐Gaussian distribution derived from the wavefunctions of the harmonic oscillator. The basic simulation method is easily extended to produce non‐Gaussian maps with a given power spectrum and diagonal bispectrum.