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The measurements of the statistical properties of the Cosmic Microwave Background (CMB) fluctuations enable us to probe the physics of the very early Universe especially at the epoch of inflation. A particular interest lays on the detection…

Cosmology and Nongalactic Astrophysics · Physics 2011-06-07 S. Pires , S. Plaszczynski , A. Lavabre

We present an analysis of the Minkowski Functionals (MFs) describing the WMAP three-year temperature maps to place limits on possible levels of primordial non-Gaussianity. In particular, we apply perturbative formulae for the MFs to give…

Probing Gaussianity represents one of the key questions in modern cosmology, because it allows to discriminate between different models of inflation. We test for large-scale non-Gaussianities in the cosmic microwave background (CMB) in a…

Cosmology and Nongalactic Astrophysics · Physics 2010-05-17 C. Raeth , G. Rossmanith , G. Morfill , A. J. Banday , K. M. Gorski

We describe a sampling method to estimate the polarized CMB signal from observed maps of the sky. We use a Metropolis-within-Gibbs algorithm to estimate the polarized CMB map, containing Q and U Stokes parameters at each pixel, and its…

We develop a method to constrain the level of non-Gaussianity of density perturbations when the 3-point function is of the "equilateral" type. Departures from Gaussianity of this form are produced by single field models such as ghost or DBI…

While the probability density function (PDF) of the cosmic microwave background (CMB) convergence field approximately follows a Gaussian distribution, primordial non-Gaussianities and small contributions from structures at low redshifts…

Cosmology and Nongalactic Astrophysics · Physics 2023-08-16 Zhuoqi Zhang , Yuuki Omori , Chihway Chang

We explore a systematic approach to the analysis of primordial non-Gaussianity using fluctuations in temperature and polarization of the Cosmic Microwave Background (CMB). Following Munshi & Heavens (2009), we define a set of power-spectra…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-18 Dipak Munshi , Peter Coles , Asantha Cooray , Alan Heavens , Joseph Smidt

Non-Gaussianity in the distribution of inflationary perturbations, measurable in statistics of the cosmic microwave background (CMB) and large scale structure fluctuations, can be used to probe non-trivial initial quantum states for these…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-17 Joyce Byun , Nishant Agarwal , Rachel Bean , Richard Holman

We present evidence for the detection of primordial non-Gaussianity of the local type (fNL), using the temperature information of the Cosmic Microwave Background (CMB) from the WMAP 3-year data. We employ the bispectrum estimator of…

Astrophysics · Physics 2008-11-26 Amit P. S. Yadav , Benjamin D. Wandelt

This is my contribution to Proceedings of the International Workshop on Cosmic Structure and Evolution, September 23-25, 2009, Bielefeld, Germany. In my talk I presented some non-Gaussian features of the foreground reduced WMAP five year…

Cosmology and Nongalactic Astrophysics · Physics 2010-11-15 Alexey Golovnev

We present a new method to estimate three-point correlations in Cosmic Microwave Background maps. Our Fast Fourier Transform based implementation estimates three-point functions using all possible configurations (triangles) at a controlled…

Astrophysics · Physics 2009-11-13 Gang Chen , Istvan Szapudi

We describe our methodology for comparing the WMAP measurements of the cosmic microwave background (CMB) and other complementary data sets to theoretical models. The unprecedented quality of the WMAP data, and the tight constraints on…

We present results from a test for the Gaussianity of the whole sky sub-degree scale CMB temperature anisotropy measured by the Wilkinson Microwave Anisotropy Probe (WMAP). We calculate the genus from the foreground-subtracted and…

Astrophysics · Physics 2010-04-06 Chan-Gyung Park

We use Minkowski Functionals to explore the presence of non-Gaussian signatures in simulated cosmic microwave background (CMB) maps. Precisely, we analyse the non-Gaussianities produced from the angular power spectra emerging from a class…

Cosmology and Nongalactic Astrophysics · Physics 2023-03-08 Camila P. Novaes , Micol Benetti , Armando Bernui

We performed a comprehensive statistical analysis using complex phases of the a_lm coefficients computed from the most recent data of the Wilkinson Microwave Anisotropy Probe (WMAP). Our aim was to confirm or constrain the presence of…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-16 András Kovács , István Szapudi , Zsolt Frei

We present a multi-class neural network (NN) classifier as a method to measure nonGaussianity, characterised by the local non-linear coupling parameter fNL, in maps of the cosmic microwave background (CMB) radiation. The classifier is…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-28 B. Casaponsa , M. Bridges , A. Curto , R. B. Barreiro , M. P. Hobson , E. Martínez-González

We introduce a new mathematical tool (a direction-dependent probe) to analyse the randomness of purported isotropic Gaussian random fields on the sphere. We apply the probe to assess the full-sky cosmic microwave background (CMB)…

Cosmology and Nongalactic Astrophysics · Physics 2020-06-29 J. Hamann , Q. T. Le Gia , I. H. Sloan , Y. G. Wang , R. S. Womersley

The 21-cm brightness temperature fluctuation from the Dark Ages ($z \simeq 30-100$) will allow us to probe the inflationary epoch on very small scales ($>0.1 \, \mbox{Mpc}^{-1}$), inaccessible to cosmic microwave background experiments.…

Cosmology and Nongalactic Astrophysics · Physics 2023-07-28 Giorgio Orlando , Thomas Flöss , P. Daniel Meerburg , Joseph Silk

Since the first limit on the (local) primordial non-Gaussianity parameter, fNL, was obtained from COBE data in 2002, observations of the CMB have been playing a central role in constraining the amplitudes of various forms of non-Gaussianity…

Cosmology and Nongalactic Astrophysics · Physics 2015-03-13 Eiichiro Komatsu

Temperature maps of the Cosmic Microwave Background (CMB) radiation, as those obtained by the Wilkinson Microwave Anisotropy Probe (WMAP), provide one of the most precise data sets to test fundamental hypotheses of modern cosmology. One of…

Astrophysics · Physics 2009-11-13 Armando Bernui , Constantino Tsallis , Thyrso Villela