Mapping possible non-Gaussianity in the Planck maps
arXiv:1405.1128 · doi:10.1051/0004-6361/201424654
Abstract
[Abridged.] It is conceivable that no single statistical estimator can be sensitive to all forms and levels of non-Gaussianity that may be present in observed CMB data. In recent works a statistical procedure based upon the calculation of the skewness and kurtosis of the patches of CMB sky-sphere has been proposed and used to find out significant large-angle deviation from Gaussianity in the foreground-reduced WMAP maps. Here we address the question as to how the analysis of Gaussianity of WMAP maps is modified if the foreground-cleaned Planck maps are used, therefore extending and complementing the previous analyses in several regards. We carry out a new analysis of Gaussianity with the available nearly full-sky foreground-cleaned Planck maps. As the foregrounds are cleaned through different component separation procedures, each of the resulting Planck maps is then tested for Gaussianity. We determine quantitatively the effects for Gaussianity of masking the foreground-cleaned Planck maps with the INPMASK, VALMASK, and U73 Planck masks. We show that although the foreground-cleaned Planck maps present significant deviation from Gaussianity of different degrees when the less severe INPMASK and VALMASK are used, they become consistent with Gaussianity as detected by our indicator when masked with the union U73 mask. A slightly smaller consistency with Gaussianity is found when the indicator is employed, which seems to be associated with large-angle anomalies reported by the Planck team. Finally, we examine the robustness of the Gaussianity analyses with respect to the noise pixel's as given by the Planck team, and show that no appreciable changes arise when is incorporated into the maps. The results of our analyses provide important information about the suitability of the foreground-cleaned Planck maps as Gaussian reconstructions of the CMB sky.
arXiv comment10 pages, 4 figures. V2: Version to appear in A&A (2014), reformatted, typos corrected, references added, a word added in the title
References in corpus (38)
- HEALPix -- a Framework for High Resolution Discretization, and Fast Analysis of Data Distributed on the Sphere
- Five-Year Wilkinson Microwave Anisotropy Probe (WMAP) Observations: Cosmological Interpretation
- Five-Year Wilkinson Microwave Anisotropy Probe (WMAP) Observations: Data Processing, Sky Maps, and Basic Results
- Non-Gaussianity from Inflation: Theory and Observations
- Weak Gravitational Lensing of the CMB
- Inflation Dynamics and Reheating
- First Year Wilkinson Microwave Anisotropy Probe (WMAP) Observations: Foreground Emission
- First Year Wilkinson Microwave Anisotropy Probe (WMAP) Observations: Tests of Gaussianity
- Single field consistency relation for the 3-point function
- Planck 2013 results. XXIII. Isotropy and statistics of the CMB
- Inflationary Cosmology
- Planck 2013 Results. XXIV. Constraints on primordial non-Gaussianity
- A full sky, low foreground, high resolution CMB map from WMAP
- Planck 2013 results. XII. Component separation
- Toward an Understanding of Foreground Emission in the BICEP2 Region
- Component separation methods for the Planck mission
- Hunting for Primordial Non-Gaussianity in the Cosmic Microwave Background
- Testing for Non-Gaussianity in the Wilkinson Microwave Anisotropy Probe Data: Minkowski Functionals and the Length of the Skeleton
- Non-Gaussianities in New Ekpyrotic Cosmology
- Non-Gaussianity in a Matter Bounce
- Non-Gaussianities from ekpyrotic collapse with multiple fields
- The performance of spherical wavelets to detect non-Gaussianity in the CMB sky
- Multi-resolution internal template cleaning: An application to the Wilkinson Microwave Anisotropy Probe 7-yr polarization data
- Mapping the large-scale anisotropy in the WMAP data
- Thermal Fluctuations and Bouncing Cosmologies
- Planck CMB Anomalies: Astrophysical and Cosmological Secondary Effects and the Curse of Masking
- A model-independent test for scale-dependent non-Gaussianities in the CMB
- Constraints on the non-linear coupling parameter fnl with the Archeops data
- Searching for non-Gaussianity in the WMAP data
- Scale dependent non-Gaussianities in the CMB data identified with Minkowski Functionals and Scaling Indices
- Non-gaussianity in the foreground-reduced CMB maps
- Searching for primordial non-Gaussianity in Planck CMB maps using a combined estimator
- Mapping the large-angle deviation from Gaussianity in simulated CMB maps
- Local properties of WMAP Cold Spot
- Scale-dependent non-Gaussianities in the WMAP data as identified by using surrogates and scaling indices
- Impact of the 1/f noise and the asymmetric beam on non-Gaussianity searches with Planck
- Impact of Instrumental Systematics on the CMB Bispectrum
- Identification of galaxy clusters in cosmic microwave background maps using the Sunyaev-Zel'dovich effect