Predictions of mixed non-Gaussian cosmological density fields for the cosmic microwave background radiation

Abstract

We present simulations of the Cosmic Microwave Background Radiation (CMBR) power spectrum for a class of mixed, non-Gaussian, primordial random fields. We assume a skew positive mixed model with adiabatic inflation perturbations plus additional isocurvature perturbations possibly produced by topological defects. The joint probability distribution used in this context is a weighted combination of Gaussian and non-Gaussian random fields, such as: P(delta) = (1-alpha)f_{1}(delta) + alpha*f_{2}(delta), where f_{1}(delta) is a Gaussian distribution, f_{2}(delta) is a non-Gaussian general distribution, and alpha is a scale dependent mixture parameter. Results from simulations of CMBR temperature and polarisation power spectra show a distinct signature for very small deviations (~ 0.1%) from a pure Gaussian field. We discuss the main properties of such mixed models as well, their predictions and suggestions on how to apply them to small scale CMBR observations. A reduced chi^2 test shows that the contribution of an isocurvature fluctuation field is not ruled out in actual CMB observations, even in WMAP first-year sky map.

28 pages, 13 PostScript figures, aas style. Accepted for publication in the ApJ (Feb 2004). Version accepted by the ApJ can be found in http://www.das.inpe.br/~alex/papers.html, just clicking in the paper's name

References in corpus (29)

• First Year Wilkinson Microwave Anisotropy Probe (WMAP) Observations: Determination of Cosmological Parameters
• A Flat Universe from High-Resolution Maps of the Cosmic Microwave Background Radiation
• MAXIMA-1: A Measurement of the Cosmic Microwave Background Anisotropy on angular scales of 10 arcminutes to 5 degrees
• 4-Year COBE DMR Cosmic Microwave Background Observations: Maps and Basic Results
• First Year Wilkinson Microwave Anisotropy Probe (WMAP) Observations: Implications for Inflation
• Wilkinson Microwave Anisotropy Probe (WMAP) First Year Observations: TE Polarization
• DASI First Results: A Measurement of the Cosmic Microwave Background Angular Power Spectrum
• Adiabatic and entropy perturbations from inflation
• First Year Wilkinson Microwave Anisotropy Probe (WMAP) Observations: Tests of Gaussianity
• The Three--Point Correlation Function of the Cosmic Microwave Background in Inflationary Models
• Large-scale structure, the cosmic microwave background, and primordial non-gaussianity
• The Anisotropy of the Microwave Background to l = 3500: Deep Field Observations with the Cosmic Background Imager
• The abundance of high-redshift objects as a probe of non-Gaussian initial conditions
• The Anisotropy of the Microwave Background to l = 3500: Mosaic Observations with the Cosmic Background Imager
• Evidence for a non-zero Lambda and a low matter density from a combined analysis of the 2dF Galaxy Redshift Survey and Cosmic Microwave Background Anisotropies
• Cosmological implications of the MAXIMA-I high resolution Cosmic Microwave Background anisotropy measurement
• The General Primordial Cosmic Perturbation
• The Angular Dependence of the Three-Point Correlation Function of the Cosmic Microwave Background Radiation as Predicted by Inflationary Cosmologies
• Non-Gaussianity of the derived maps from the first-year WMAP data
• Evidence for non-Gaussianity in the COBE DMR Four Year Sky Maps
• Keck Spectroscopy and NICMOS Photometry of a Redshift z=5.60 Galaxy
• Correlated perturbations from inflation and the cosmic microwave background
• COSMICS: Cosmological Initial Conditions and Microwave Anisotropy Codes
• Constraints on a non-gaussian (${\chi }_m^2$) CDM model
• Extended Perturbation Theory for the Local Density Distribution Function
• Evolution of the cosmological density distribution function
• Cosmological Parameters
• Small Deviations from Gaussianity and The Galaxy Cluster Abundance Evolution
• The 1-Point Cluster Distribution Function and its Moments

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• Correlated Mixture Between Adiabatic and Isocurvature Fluctuations and Recent CMB Observations
• High Order Correction Terms for The Peak-Peak Correlation Function in Nearly-Gaussian Models