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Statistical isotropy is often assumed in cosmology and should be tested rigorously against observational data. We construct simple quadratic estimators to reconstruct asymmetry in the primordial power spectrum from CMB temperature and…

Cosmology and Nongalactic Astrophysics · Physics 2014-05-16 Yin-Zhe Ma , George Efstathiou , Anthony Challinor

The primordial power spectrum describes the initial perturbations in the Universe which eventually grew into the large-scale structure we observe today, and thereby provides an indirect probe of inflation or other structure-formation…

Cosmology and Nongalactic Astrophysics · Physics 2014-07-02 P. Paykari , F. Lanusse , J. -L. Starck , F. Sureau , J. Bobin

Measuring the deviation from scale invariance of the primordial power spectrum is a critical test of inflation. In this paper we reconstruct the shape of the primordial power spectrum of curvature perturbations from the cosmic microwave…

Cosmology and Nongalactic Astrophysics · Physics 2011-09-01 Zong-Kuan Guo , Dominik J. Schwarz , Yuan-Zhong Zhang

Current analyses of the Lyman-alpha forest assume that the primordial power spectrum of density perturbations obeys a simple power law, a strong theoretical assumption which should be tested. Employing a large suite of numerical simulations…

Cosmology and Nongalactic Astrophysics · Physics 2010-05-24 Simeon Bird

We constrain the shape of the primordial power spectrum using recent measurements of the cosmic microwave background (CMB) from the Wilkinson Microwave Anisotropy Probe (WMAP) 7-year data and other high-resolution CMB experiments. We also…

Cosmology and Nongalactic Astrophysics · Physics 2012-06-27 J. Alberto Vazquez , A. N. Lasenby , M. Bridges , M. P. Hobson

Using the temperature data from Planck we search for departures from a power-law primordial power spectrum, employing Bayesian model-selection and posterior probabilities. We parametrize the spectrum with $n$ knots located at arbitrary…

Cosmology and Nongalactic Astrophysics · Physics 2014-08-28 Grigor Aslanyan , Layne C. Price , Kevork N. Abazajian , Richard Easther

Reconstructing the shape of the primordial power spectrum in a model independent way from cosmological data is a useful consistency check on what is usually assumed regarding early universe physics. It is also our primary window to unknown…

Astrophysics · Physics 2008-11-26 Pia Mukherjee , Yun Wang

In inflationary models with minimal amount of gravity waves, the primordial power spectrum of density fluctuations, $A_S^2(k)$, together with the basic cosmological parameters, completely specify the predictions for the cosmic microwave…

Astrophysics · Physics 2009-10-31 Yun Wang , David N. Spergel , Michael A. Strauss

We consider the possibility that the primordial curvature perturbation is direction-dependent. To first order this is parameterised by a quadrupolar modulation of the power spectrum and results in statistical anisotropy of the CMB, which…

Cosmology and Nongalactic Astrophysics · Physics 2018-02-15 Amel Durakovic , Paul Hunt , Suvodip Mukherjee , Subir Sarkar , Tarun Souradeep

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

The basic cosmological parameters and the primordial power spectrum together completely specify predictions for the cosmic microwave background radiation anisotropy and large scale structure. Here we show how we can strongly constrain both…

Astrophysics · Physics 2010-11-30 Yun Wang , David N. Spergel , Michael A. Strauss

The primordial curvature fluctuation spectrum is reconstructed by the maximum likelihood reconstruction method using the five-year Wilkinson Microwave Anisotropy Probe data of the cosmic microwave background temperature anisotropy. We apply…

Astrophysics · Physics 2009-02-19 Ryo Nagata , Jun'ichi Yokoyama

We develop a method to reconstruct the primordial power spectrum, P(k), using both temperature and polarisation data from the joint analysis of a number of Cosmic Microwave Background (CMB) observations. The method is an extension of the…

Cosmology and Nongalactic Astrophysics · Physics 2009-07-22 Gavin Nicholson , Carlo R. Contaldi

The preferred shape for the primordial spectrum of curvature perturbations is determined by performing a Bayesian model selection analysis of cosmological observations. We first reconstruct the spectrum modelled as piecewise linear in \log…

Cosmology and Nongalactic Astrophysics · Physics 2012-06-27 J. Alberto Vazquez , M. Bridges , M. P. Hobson , A. N. Lasenby

Detailed knowledge of the primordial power spectrum of curvature perturbations is essential both in order to elucidate the physical mechanism (`inflation') which generated it, and for estimating the cosmological parameters from observations…

Cosmology and Nongalactic Astrophysics · Physics 2014-01-17 Paul Hunt , Subir Sarkar

We investigate a set of cosmological models for which the primordial power spectrum has a large-scale power deficit. The standard power-law spectrum is subject to long-wavelength modifications described by some new parameters, resulting in…

Cosmology and Nongalactic Astrophysics · Physics 2019-08-13 Sandro D. P. Vitenti , Patrick Peter , Antony Valentini

We allow a more general (step-function) form of the primordial power spectrum than the usual featureless power-law Harrison--Zeldovich (with spectral index n=1) power spectrum, and fit it to the latest Cosmic Microwave Background data sets.…

Astrophysics · Physics 2009-11-07 O. Elgaroy , M. Gramann , O. Lahav

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

Pursuing the original idea proposed in our previous paper (Paper I), we improve the method to determine the shape of the initial curvature perturbation spectrum $P(k)$ from the CMB data. The thickness of the last scattering surface (LSS)…

Astrophysics · Physics 2009-10-09 Makoto Matsumiya , Misao Sasaki , Jun'ichi Yokoyama

We measure the three-dimensional cross-power spectrum of galaxy density and intrinsic alignment (IA) fields for the first time from the spectroscopic and imaging data of SDSS-III BOSS galaxies, for each of the four samples in the redshift…

Cosmology and Nongalactic Astrophysics · Physics 2025-09-09 Toshiki Kurita , Masahiro Takada