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We investigate how well future large-scale radio surveys could measure different shapes of primordial non-Gaussianity; in particular we focus on angle-dependent non-Gaussianity arising from primordial anisotropic sources, whose bispectrum…

The large-scale clustering of galaxies can serve as a probe of primordial non-Gaussianity in the Universe competitive with the anisotropies of the CMB. Here, we present improved theoretical predictions which include an important, previously…

宇宙学与河外天体物理 · 物理学 2015-03-19 Vincent Desjacques , Donghui Jeong , Fabian Schmidt

The non-Gaussianity of initial perturbations provides information on the mechanism that generated primordial density fluctuations. The expected non-Gaussianity for slow-roll inflationary models is well below the ultimate detection level…

天体物理学 · 物理学 2008-11-26 Asantha Cooray

We outline the expected constraints on non-Gaussianity from the cosmic microwave background (CMB) with current and future experiments, focusing on both the third (f_{NL}) and fourth-order (g_{NL} and \tau_{NL}) amplitudes of the local…

宇宙学与河外天体物理 · 物理学 2010-07-27 Joseph Smidt , Alexandre Amblard , Christian T. Byrnes , Asantha Cooray , Alan Heavens , Dipak Munshi

The most direct probe of non-Gaussian initial conditions has come from bispectrum measurements of temperature fluctuations in the Cosmic Microwave Background and of the matter and galaxy distribution at large scales. Such bispectrum…

宇宙学与河外天体物理 · 物理学 2015-05-18 M. Liguori , E. Sefusatti , J. R. Fergusson , E. P. S. Shellard

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…

We derive a general expression for the probability of observing deviations from statistical isotropy in the cosmic microwave background (CMB) if the primordial fluctuations are non-Gaussian and extend to superhorizon scales. The primary…

宇宙学与河外天体物理 · 物理学 2016-01-27 Saroj Adhikari , Sarah Shandera , Adrienne L. Erickcek

We present the angular power spectrum derived from the first-year Wilkinson Microwave Anisotropy Probe (WMAP) sky maps. We study a variety of power spectrum estimation methods and data combinations and demonstrate that the results are…

Wilkinson Microwave Anisotropy Probe (WMAP) 3-year data confirm the ellipticity of anisotropies of Cosmic Microwave Background (CMB) maps, found previously for Boomerang and WMAP 1-year high sensitivity maps. The low noise level of the WMAP…

天体物理学 · 物理学 2008-11-26 V. G. Gurzadyan , C. L. Bianco , A. L. Kashin , H. Kuloghlian , G. Yegorian

We present results from a first test of the Gaussianity of degree-scale cosmic microwave background (CMB) anisotropy. We investigate Gaussianity of the CMB anisotropy by studying the topology of CMB anisotropy maps from the QMAP and…

天体物理学 · 物理学 2009-10-07 Chan-Gyung Park , Changbom Park , Bharat Ratra , Max Tegmark

The identification of non-Gaussian signatures in cosmic microwave background (CMB) temperature maps is one of the main cosmological challenges today. We propose and investigate altenative methods to analyse CMB maps. Using the technique of…

天体物理学 · 物理学 2009-11-07 C. Raeth , P. Schuecker

We discuss models of primordial density perturbations where the non-Gaussianity is strongly scale-dependent. In particular, the non-Gaussianity may have a sharp cut-off and be very suppressed on large cosmological scales, but sizeable on…

宇宙学与河外天体物理 · 物理学 2011-02-18 Antonio Riotto , Martin S. Sloth

The first-year Wilkinson Microwave Anisotropy Probe data suggest a high optical depth for Thomson scattering of 0.17 +/- 0.04, implying that the universe was reionized at an early epoch, z ~ 20. Such early reionization is likely to be…

天体物理学 · 物理学 2009-11-10 Xuelei Chen , Asantha Cooray , Naoki Yoshida , Naoshi Sugiyama

We derive analytical formulae for the Minkowski Functions of the cosmic microwave background (CMB) and large-scale structure (LSS) from primordial non-Gaussianity. These formulae enable us to estimate a non-linear coupling parameter, f_NL,…

天体物理学 · 物理学 2011-02-11 Chiaki Hikage , Eiichiro Komatsu , Takahiko Matsubara

We use simulated maps of the cosmic microwave background anisotropy to quantify the ability of different statistical tests to discriminate between Gaussian and non-Gaussian models. Despite the central limit theorem on large angular scales,…

天体物理学 · 物理学 2009-10-31 Nicholas G. Phillips , A. Kogut

We present up-to-date constraints on the value of the fine-structure constant at the epoch of decoupling from the recent observations made by the Wilkinson Microwave Anisotropy Probe (WMAP) satellite. In the framework of models we…

天体物理学 · 物理学 2008-11-26 C. J. A. P. Martins , A. Melchiorri , G. Rocha , R. Trotta , P. P. Avelino , P. Viana

We confront predictions of inflationary scenarios with the WMAP data, in combination with complementary small-scale CMB measurements and large-scale structure data. The WMAP detection of a large-angle anti-correlation in the…

We forecast combined future constraints from the cosmic microwave background and large-scale structure on the models of primordial non-Gaussianity. We study the generalized local model of non-Gaussianity, where the parameter f_NL is…

宇宙学与河外天体物理 · 物理学 2015-06-05 Adam Becker , Dragan Huterer , Kenji Kadota

The first three years of observation of the Wilkinson Microwave Anisotropy Probe (WMAP) have provided the most precise data on the anisotropies of the cosmic microwave background (CMB) to date. We investigate the impact of these results and…

天体物理学 · 物理学 2008-11-26 Michael Doran , Georg Robbers , Christof Wetterich

[Abridged] In recent works we have proposed two new large-angle non-Gaussianity indicators based on skewness and kurtosis of patches of CMB sky-sphere, and used them to find out significant deviation from Gaussianity in frequency bands and…

宇宙学与河外天体物理 · 物理学 2012-02-15 A. Bernui , M. J. Reboucas