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Related papers: Direct search for features in the primordial bispe…

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We discuss cosmic microwave background anisotropies in models with an unconventional primordial power spectrum. In particular, we consider an initial power spectrum with some ``spiky'' corrections. Interestingly, such a primordial power…

Astrophysics · Physics 2010-04-05 Masahiro Kawasaki , Fuminobu Takahashi , Tomo Takahashi

We use the modified Richardson-Lucy deconvolution algorithm to reconstruct the Primordial Power Spectrum from the Weak Lensing Power spectrum reconstructed from the CMB anisotropies. This provides an independent window to observe and…

Cosmology and Nongalactic Astrophysics · Physics 2021-04-27 Rajorshi Sushovan Chandra , Tarun Souradeep

It is often assumed that primordial perturbations are statistically isotropic, which implies, among other properties, that their power spectrum is invariant under rotations. In this article, we test this assumption by placing…

Astrophysics · Physics 2009-02-23 C. Armendariz-Picon , Larne Pekowsky

The observed angular power spectrum of the cosmic microwave background temperature anisotropy, $C_l$, is a convolution of a cosmological radiative transport kernel with an assumed primordial power spectrum of inhomogeneities. Exquisite…

Astrophysics · Physics 2009-11-10 Arman Shafieloo , Tarun Souradeep

A small deviation from scale invariance in the form of oscillations in the primordial correlation spectra has been predicted by various cosmological models. In this paper we review a recently developed method to search for these features in…

Cosmology and Nongalactic Astrophysics · Physics 2014-08-22 P. Daniel Meerburg , David N. Spergel , Benjamin D. Wandelt

We compute the cosmic microwave background temperature bispectrum generated by nonlinearities at recombination on all scales. We use CosmoLib$2^{\rm nd}$, a numerical Boltzmann code at second-order to compute CMB bispectra on the full sky.…

Cosmology and Nongalactic Astrophysics · Physics 2015-04-08 Zhiqi Huang , Filippo Vernizzi

Various data analyses of the Cosmic Microwave Background (CMB) provide observational hints of statistical isotropy breaking. Some of these features can be studied within the framework of primordial vector fields in inflationary theories…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-28 N. Bartolo , E. Dimastrogiovanni , M. Liguori , S. Matarrese , A. Riotto

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

The {\em Planck} DR3 measurements of the temperature and polarization anisotropies power spectra of the cosmic microwave background (CMB) show an excess of smoothing of the acoustic peaks with respect to $\Lambda$CDM, often quantified by a…

Cosmology and Nongalactic Astrophysics · Physics 2022-10-26 Mario Ballardini , Fabio Finelli

Recent cosmic microwave background (CMB) observations put strong constraints on the spatial curvature via estimation of the parameter $\Omega_k$ assuming an almost scale invariant primordial power spectrum. We study the evolution of the…

Cosmology and Nongalactic Astrophysics · Physics 2016-10-31 Béatrice Bonga , Brajesh Gupt , Nelson Yokomizo

The simplest inflationary models predict the primordial power spectrum (PPS) of curvature perturbations to be nearly scale-invariant. However, various other models of inflation predict deviations from this behaviour, motivating a…

Cosmology and Nongalactic Astrophysics · Physics 2025-09-03 Subarna Chaki , Andrina Nicola , Alessio Spurio Mancini , Davide Piras , Robert Reischke

Several early Universe scenarios predict a direction-dependent spectrum of primordial curvature perturbations. This translates into the violation of the statistical isotropy of cosmic microwave background radiation. Previous searches for…

Cosmology and Nongalactic Astrophysics · Physics 2017-03-22 S. Ramazanov , G. Rubtsov , M. Thorsrud , F. R. Urban

The stochastic gravitational wave background (SGWB) provides a unique opportunity to probe the early Universe, potentially encoding information about the primordial curvature power spectrum and the energy scale of reheating. Recent…

Cosmology and Nongalactic Astrophysics · Physics 2024-07-23 Lele Fan , Jie Zheng , Fengge Zhang , Zhi-Qiang You

Recent analysis of the WMAP and Planck data have shown the presence of a dip and a bump in the spectrum of primordial perturbations at the scales $k=0.002$ Mpc${}^{-1}$ and $k=0.0035$ Mpc${}^{-1}$ respectively. We analyze for the first time…

Cosmology and Nongalactic Astrophysics · Physics 2017-04-19 Alexander Gallego Cadavid , Antonio Enea Romano , Stefano Gariazzo

We evaluate the angular bispectrum of the CMB temperature anisotropy at large angular scale due to a stochastic background of primordial magnetic fields. The shape of non-Gaussianity depends on the spectral index of the magnetic field power…

Cosmology and Nongalactic Astrophysics · Physics 2009-10-02 Chiara Caprini , Fabio Finelli , Daniela Paoletti , Antonio Riotto

Quasi-single field inflation predicts a peculiar momentum dependence in the squeezed limit of the primordial bispectrum which smoothly interpolates between the local and equilateral models. This dependence is directly related to the mass of…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-04 Emiliano Sefusatti , James R. Fergusson , Xingang Chen , E. P. S. Shellard

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…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-18 M. Liguori , E. Sefusatti , J. R. Fergusson , E. P. S. Shellard

Angular power spectrum of the cosmic microwave background (CMB) temperature anisotropies is one of the most important on characteristics of the Universe such as its geometry and total density. Using flat sky approximation and Fourier…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-30 Lung-Yih Chiang , Fei-Fan Chen

We have developed a fast method for predicting the angular power spectrum, C_l, of the cosmic microwave background given cosmological parameters and a primordial power spectrum of perturbations. After pre--computing the radiation…

Astrophysics · Physics 2009-11-07 Manoj Kaplinghat , Lloyd Knox , Constantinos Skordis