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With the recently published Cosmic Microwave Background data from Planck we address the optimized binning of the primordial power spectrum. As an important modification to the usual binning of the primordial spectrum, along with the…

宇宙学与河外天体物理 · 物理学 2014-01-06 Dhiraj Kumar Hazra , Arman Shafieloo , George F. Smoot

We employ a pixel-based likelihood technique to estimate the angular power spectrum of the COBE Differential Microwave Radiometer (DMR) 4-year sky maps. The spectrum is consistent with a scale-invariant power-law form with a normalization,…

天体物理学 · 物理学 2009-10-28 G. Hinshaw , A. J. Banday , C. L. Bennett , K. M. Gorski , A. Kogut , G. F. Smoot , E. L. Wright

We explore a class of primordial power spectra that can fit the observed anisotropies in the cosmic microwave background well and that predicts a value for the Hubble parameter consistent with the local measurement of $H_0 = 74$ km/s/Mpc.…

宇宙学与河外天体物理 · 物理学 2020-10-14 Ryan E. Keeley , Arman Shafieloo , Dhiraj Kumar Hazra , Tarun Souradeep

We investigate a non-parametric Bayesian method for reconstructing the primordial power spectrum (PPS) of scalar perturbations using temperature and polarisation data from the {\em Planck}, ACT, and SPT CMB experiments. This reconstruction…

宇宙学与河外天体物理 · 物理学 2025-07-30 Antonio Raffaelli , Mario Ballardini

We use the localized principle component analysis to detect deviations from scale invariance of the primordial power spectrum of curvature perturbations. With the technique we make uncorrelated estimates of the primordial power spectrum…

宇宙学与河外天体物理 · 物理学 2011-12-25 Zong-Kuan Guo , Yuan-Zhong Zhang

We examine the constraints cosmological observations can place on any trans-Planckian corrections to the primordial spectrum of perturbations underlying the anisotropies in the Cosmic Microwave Background. We focus on models of…

天体物理学 · 物理学 2011-05-12 Richard Easther , William H Kinney , Hiranya Peiris

Given observations of B-mode polarization power spectrum of the cosmic microwave background (CMB), we can reconstruct power spectra of primordial tensor modes from the early Universe without assuming their functional form such as a…

宇宙学与河外天体物理 · 物理学 2018-06-20 Takashi Hiramatsu , Eiichiro Komatsu , Masashi Hazumi , Misao Sasaki

The combined analysis of the cosmic microwave background on large scales and Lyman-alpha forest on small scales provides a sufficiently long lever arm to obtain strong constraints on the slope and curvature of the power spectrum of…

天体物理学 · 物理学 2009-11-10 Matteo Viel , Jochen Weller , Martin Haehnelt

In this work we explore the power of future large-scale surveys to constrain possible deviations from the standard single-field slow-roll inflationary scenario. Specifically, we parametrize possible fluctuations around the almost…

宇宙学与河外天体物理 · 物理学 2021-05-14 Muhammad Sadegh Esmaeilian , Marzieh Farhang , Shirin Khodabakhshi

Current results from the Lyman alpha forest assume that the primordial power spectrum of density perturbations follows a simple power law form, with running. We present the first analysis of Lyman alpha data to study the effect of relaxing…

宇宙学与河外天体物理 · 物理学 2011-05-16 Simeon Bird , Hiranya V. Peiris , Matteo Viel , Licia Verde

We use Bayesian inference and nested sampling to develop a non-parametric method to reconstruct the primordial power spectrum $P_{\mathcal{R}}(k)$ from Large Scale Structure (LSS) data. The performance of the method is studied by applying…

宇宙学与河外天体物理 · 物理学 2024-07-16 G. Martínez-Somonte , A. Marcos-Caballero , E. Martínez-González , G. Cañas-Herrera

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…

天体物理学 · 物理学 2009-02-23 C. Armendariz-Picon , Larne Pekowsky

We present the first results from a Bayesian analysis of the WMAP first year data using a Gibbs sampling technique. Using two independent, parallel supercomputer codes we analyze the WMAP Q, V and W bands. The analysis results in a full…

There has been growing interest in the possibility of testing more precisely the assumption of statistical isotropy of primordial density perturbations. If it is to be tested with galaxy surveys at distance scales <~ 10 Mpc, then nonlinear…

天体物理学 · 物理学 2008-11-26 Shin'ichiro Ando , Marc Kamionkowski

The formation of primordial black holes or other dark matter relics from amplified density fluctuations in the early universe may also generate scalar-induced gravitational waves (GW), carrying vital information about the primordial power…

宇宙学与河外天体物理 · 物理学 2025-12-25 Aya Ghaleb , Ameek Malhotra , Gianmassimo Tasinato , Ivonne Zavala

Fourier analysis and power spectrum estimation of the cosmic microwave background anisotropy on an incompletely sampled sky developed by Gorski (1994) has been applied to the high-latitude portion of the 4-year COBE DMR 31.5, 53 and 90 GHz…

天体物理学 · 物理学 2009-10-28 K. M. Gorski , A. J. Banday , C. L. Bennett , G. Hinshaw , A. Kogut , G. F. Smoot , E. L. Wright

The angular power spectrum estimator developed by Peebles (1973) and Hauser & Peebles (1973) has been modified and applied to the 4 year maps produced by the COBE DMR. The power spectrum of the observed sky has been compared to the power…

天体物理学 · 物理学 2008-11-26 E. L. Wright , C. L. Bennett , K. Gorski , G. Hinshaw , G. F. Smoot

We present three non-parametric Bayesian primordial reconstructions using Planck 2018 polarization data: linear spline primordial power spectrum reconstructions, cubic spline inflationary potential reconstructions and sharp-featured…

宇宙学与河外天体物理 · 物理学 2019-11-20 Will J. Handley , Anthony N. Lasenby , Hiranya V. Peiris , Michael P. Hobson

We propose a straightforward and model independent methodology for characterizing the sensitivity of CMB and other experiments to wiggles, irregularities, and features in the primordial power spectrum. Assuming that the primordial…

宇宙学与河外天体物理 · 物理学 2015-06-11 Christopher Gauthier , Martin Bucher

We search a sample of photometric luminous red galaxies (LRGs) measured by the Sloan Digital Sky Survey (SDSS) for a quadrupolar anisotropy in the primordial power spectrum, in which P(\vec{k}) is an isotropic power spectrum P(k) multiplied…

宇宙学与河外天体物理 · 物理学 2010-05-25 Anthony R. Pullen , Christopher M. Hirata