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We present two novel methods for the estimation of the angular power spectrum of cosmic microwave background (CMB) anisotropies. We assume an absolute CMB experiment with arbitrary asymmetric beams and arbitrary sky coverage. The methods…

Cosmology and Nongalactic Astrophysics · Physics 2017-01-25 Elina Keihänen , Kimmo Kiiveri , Hannu Kurki-Suonio , Martin Reinecke

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 studied electron correlations in the doped two-dimensional (2D) Hubbard model by using the coupled-cluster method (CCM) to investigate whether or not the method can be applied to correct the independent particle approximations…

Strongly Correlated Electrons · Physics 2009-10-31 Yoshihiro Asai , Hideki Katagiri

We demonstrate an approach that allows separating two-point correlations created by a Gaussian random field from correlations created by cosmic foregrounds such as polarized dust emission, gravitational lensing and other non-Gaussian…

Cosmology and Nongalactic Astrophysics · Physics 2024-11-26 D. I. Novikov , K. O. Parfenov

The angular power spectrum C_l is extracted from the 4 year COBE DMR data with a 20 degree galactic cut, using the narrowest window functions possible. The average power in eight multipole bands is also computed, and plotted together with a…

Astrophysics · Physics 2009-10-28 Max Tegmark

We propose and implement a fast, universally applicable method for extracting the angular power spectrum C_l from CMB temperature maps by first estimating the correlation function \xi(\theta). Our procedure recovers the C_l's using N^2 (but…

Weak lensing of CMB anisotropies and polarization for the power spectra and higher order statistics can be handled directly in harmonic-space without recourse to real-space correlation functions. For the power spectra, this approach not…

Astrophysics · Physics 2009-10-31 Wayne Hu

Two-point correlation functions of cosmic microwave background polarization provide a physically independent probe of the surprising suppression of correlations in the cosmic microwave background temperature anisotropies at large angular…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-17 Amanda Yoho , Simone Aiola , Craig J. Copi , Arthur Kosowsky , Glenn D. Starkman

Modeling the large-scale structure of the universe on nonlinear scales has the potential to substantially increase the science return of upcoming surveys by increasing the number of modes available for model comparisons. One way to achieve…

Cosmology and Nongalactic Astrophysics · Physics 2016-11-30 Marcel Schmittfull , Zvonimir Vlah

Observations show that the Cosmic Microwave Background (CMB) contains tiny variations at the 10^{-5} level around its black-body equilibrium temperature. The detection of these temperature fluctuations provides to modern Cosmology evidence…

Astrophysics · Physics 2015-06-24 Armando Bernui

The primordial curvature fluctuation spectrum is reconstructed by the cosmic inversion method using the five-year WMAP data of the cosmic microwave background temperature anisotropy. We apply the covariance matrix analysis and decompose the…

Astrophysics · Physics 2008-12-30 Ryo Nagata , Jun'ichi Yokoyama

Estimation of the angular power spectrum of the Cosmic Microwave Background (CMB) on a small patch of sky is usually plagued by serious spectral leakage, specially when the map has a hard edge. Even on a full sky map, point source masks can…

Astrophysics · Physics 2009-11-06 Sudeep Das , Amir Hajian , David N. Spergel

Cosmic microwave background (CMB) lensing is an integrated effect whose kernel is greater than half the peak value in the range $1<z<5$. Measuring this effect offers a powerful tool to probe the large-scale structure of the Universe at high…

Cosmology and Nongalactic Astrophysics · Physics 2019-03-27 Toshiya Namikawa , Benjamin Bose , François R. Bouchet , Ryuichi Takahashi , Atsushi Taruya

Asymmetric beams can create significant bias in estimates of the power spectra from CMB experiments. With the temperature power spectrum many orders of magnitude stronger than the B-mode power spectrum any systematic error that couples the…

Cosmology and Nongalactic Astrophysics · Physics 2017-03-08 Christopher G. R. Wallis , Michael L. Brown , Richard A. Battye , Giampaolo Pisano , Luca Lamagna

We introduce a rigorous definition of general power-spectrum responses as resummed vertices with two hard and $n$ soft momenta in cosmological perturbation theory. These responses measure the impact of long-wavelength perturbations on the…

Cosmology and Nongalactic Astrophysics · Physics 2017-11-03 Alexandre Barreira , Fabian Schmidt

Power spectra always play an important role in the theory of inflation. In particular, the ability to reproduce the galaxy matter power spectrum and the CMB temperature angular power spectrum coefficients to high accuracy is often…

General Relativity and Quantum Cosmology · Physics 2019-11-01 Herbert W. Hamber , Lu Heng Sunny Yu

We present a new method for time-efficient and accurate extraction of the power spectrum from future cosmic microwave background (CMB) maps based on properties of peaks and troughs of the Gaussian CMB sky. We construct a statistic…

Astrophysics · Physics 2009-11-06 A. Kashlinsky , C. Hernández--Monteagudo , F. Atrio--Barandela

We present a simple approximation that can speed up the computation of the mode-coupling matrices, which are usually the bottleneck for computing unbiased angular power spectra, as well as their associated covariance matrices, of the cosmic…

Cosmology and Nongalactic Astrophysics · Physics 2021-01-04 Thibaut Louis , Sigurd Naess , Xavier Garrido , Anthony Challinor

We present measurements of the angular two-point galaxy correlation function, $w(theta)$, from the APM Galaxy Survey. The performance of various estimators of $w$ is assessed using simulated galaxy catalogues and analytic arguments. Several…

Astrophysics · Physics 2015-06-24 S. J. Maddox , G. Efstathiou , W. J. Sutherland

The influence of large-scale density fluctuations on structure formation on small scales is described by the three-point correlation function (bispectrum) in the so-called "squeezed configurations," in which one wavenumber, say $k_3$, is…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-19 Chi-Ting Chiang , Christian Wagner , Fabian Schmidt , Eiichiro Komatsu