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We investigate the effect of primordial non-Gaussianity on the cross-correlation between the CMB anisotropies and the 21 cm fluctuations from the epoch of reionization. We assume an analytic reionization model and an ionization fraction…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-05 Hiroyuki Tashiro , Shirley Ho

Gaussianity and statistical isotropy of the Universe are modern cosmology's minimal set of hypotheses. In this work we introduce a new statistical test to detect observational deviations from this minimal set. By defining the temperature…

Cosmology and Nongalactic Astrophysics · Physics 2009-09-30 Thiago S. Pereira , L. Raul Abramo

We propose a method to probe higher-order correlators of the primordial density field through the inhomogeneity of local non-Gaussian parameters, such as f_NL, measured within smaller patches of the sky. Correlators between n-point…

Cosmology and Nongalactic Astrophysics · Physics 2012-09-28 Christian T. Byrnes , Sami Nurmi , Gianmassimo Tasinato , David Wands

Enormous information about interactions is contained in the non-Gaussianities of the primordial curvature perturbations, which are essential to break the degeneracy of inflationary models. We study the primordial bispectra for G-inflation…

Cosmology and Nongalactic Astrophysics · Physics 2021-04-21 Fengge Zhang , Yungui Gong , Jiong Lin , Yizhou Lu , Zhu Yi

We investigate the relative sensitivities of several tests for deviations from Gaussianity in the primordial distribution of density perturbations. We consider models for non-Gaussianity that mimic that which comes from inflation as well as…

Astrophysics · Physics 2009-10-31 Licia Verde , Raul Jimenez , Marc Kamionkowski , Sabino Matarrese

We simulate CMB maps including non-Gaussianity arising from cubic order perturbations of the primordial gravitational potential, characterized by the non-linearity parameter $g_{NL}$. The maps are used to study the characteristic nature of…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-13 Pravabati Chingangbam , Changbom Park

While the simplest inflationary models predict the primordial perturbations to be near scale-invariant, the primordial power spectrum (PPS) can exhibit oscillatory features in many physically well-motivated models. We search for hints of…

Cosmology and Nongalactic Astrophysics · Physics 2023-12-04 Wuhyun Sohn , Arman Shafieloo , Dhiraj Kumar Hazra

The Cosmic Microwave Background (CMB) radiation lensing is a promising tool to study the physics of early universe. In this work we probe the imprints of deviations from isotropy and scale invariance of primordial curvature perturbation…

Cosmology and Nongalactic Astrophysics · Physics 2016-06-01 Farbod Hassani , Shant Baghram , Hassan Firouzjahi

Observations by Planck indicate that CMB anisotropies are consistent with predictions of nearly Gaussian primordial perturbations as the one generated in slow-roll inflation. On the other hand, loop quantum cosmology (LQC) generates a…

Cosmology and Nongalactic Astrophysics · Physics 2024-10-02 Roshna K , V. Sreenath

We present posterior likelihoods and Bayesian model selection analysis for generalized cosmological models where the primordial perturbations include correlated adiabatic and cold dark matter isocurvature components. We perform nested…

Cosmology and Nongalactic Astrophysics · Physics 2009-12-30 Jussi Valiviita , Tommaso Giannantonio

When constraining the primordial non-Gaussianity parameter f_NL with cosmic microwave background anisotropy maps, the bias resulting from the covariance between primordial non-Gaussianity and secondary non-Gaussianities to the estimator of…

Astrophysics · Physics 2008-11-26 Paolo Serra , Asantha Cooray

It is possible to classify pixels of a smoothed cosmic microwave background (CMB) fluctuation map according to their local curvature in ``hill'', ``lake'' and ``saddle'' regions. In the Gaussian case, fractional areas occupied by pixels of…

Astrophysics · Physics 2011-05-10 O. Doré , S. Colombi , F. R. Bouchet

We present a complete set of formulae for calculating the bispectra of CMB temperature and polarization anisotropies generated from non-Gaussianity in the vector and tensor mode perturbations. In the all-sky analysis it is found that the…

Cosmology and Nongalactic Astrophysics · Physics 2010-11-11 Maresuke Shiraishi , Shuichiro Yokoyama , Daisuke Nitta , Kiyotomo Ichiki , Keitaro Takahashi

In the context of the present and future Cosmic Microwave Background (CMB) experiments, going beyond the information provided by the power spectrum has become necessary in order to tightly constrain the cosmological model. The non-Gaussian…

Astrophysics · Physics 2008-11-26 N. Aghanim , M. Kunz , P. G. Castro , O. Forni

We investigate the signature of primordial non-Gaussianities in the weak lensing bispectrum, in particular the signals generated by local, orthogonal and equilateral non-Gaussianities. The questions we address include the signal-to-noise…

Cosmology and Nongalactic Astrophysics · Physics 2013-03-07 Bjoern Malte Schaefer , Alessandra Grassi , Mischa Gerstenlauer , Christian T. Byrnes

We present a Gaussianity test of the cosmic microwave background (CMB) polarization by analyzing the statistics of unpolarized points in the sky, classified into three distinct types: saddles, comets, and beaks. This classification of…

Cosmology and Nongalactic Astrophysics · Physics 2025-12-01 K. O. Parfenov , D. I. Novikov , A. O. Mihalchenko

We develop a methodology for estimating parity-odd bispectra in the cosmic microwave background (CMB). This is achieved through the extension of the original separable modal methodology to parity-odd bispectrum domains ($\ell_1 + \ell_2 +…

Cosmology and Nongalactic Astrophysics · Physics 2014-05-12 Maresuke Shiraishi , Michele Liguori , James R. Fergusson

We investigate the statistical power of higher-order statistics and cross-correlation statistics to constrain the primordial non-Gaussianity from the imaging surveys. In particular, we consider the local-type primordial non- Gaussianity and…

Cosmology and Nongalactic Astrophysics · Physics 2016-06-08 Ichihiko Hashimoto , Atsushi Taruya , Takahiko Matsubara , Toshiya Namikawa , Shuichiro Yokoyama

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…

Cosmology and Nongalactic Astrophysics · Physics 2016-01-27 Saroj Adhikari , Sarah Shandera , Adrienne L. Erickcek

We propose and develop a formalism to describe and constrain statistically anisotropic primordial perturbations. Starting from a decomposition of the primordial power spectrum in spherical harmonics, we find how the temperature fluctuations…

Astrophysics · Physics 2009-11-13 C. Armendariz-Picon
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