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Pulsar dynamic spectra sometimes show organised interference patterns; these patterns have been shown to have power spectra which often take the form of parabolic arcs, or sequences of inverted parabolic arclets whose apexes themselves…

Astrophysics · Physics 2009-11-10 Mark Walker , Don Melrose , Dan Stinebring , Chengmin Zhang

The linear matter power spectrum is an essential ingredient in all theoretical models for interpreting large-scale-structure observables. Although Boltzmann codes such as CLASS or CAMB are very efficient at computing the linear spectrum,…

Cosmology and Nongalactic Astrophysics · Physics 2022-06-20 Giovanni Aricò , Raul E. Angulo , Matteo Zennaro

In the era of precision cosmology, establishing the correct magnitude of statistical errors in cosmological parameters is of crucial importance. However, widely used approximations in galaxy surveys analyses can lead to parameter…

Cosmology and Nongalactic Astrophysics · Physics 2020-10-07 Nicola Bellomo , José Luis Bernal , Giulio Scelfo , Alvise Raccanelli , Licia Verde

We study the angular deflection of the circular polarized components of a linearly polarized probe field in a weakly birefringent atomic system in tripod configuration. A spatially inhomogeneous control field incident obliquely onto an…

Quantum Physics · Physics 2016-12-06 Pardeep Kumar , Shubhrangshu Dasgupta

This paper presents an analytical formula that closely approximates the fully nonlinear power spectrum of matter fluctuations for redshift $z\approx 5$ to 0 over a wide range of cosmologically interesting flat models with varying matter…

Astrophysics · Physics 2009-10-30 Chung-Pei Ma

In this study, the properties of an oscillating system composed of a pendulum connected to a seesaw and placed on a moving platform with a certain slope are analyzed. Using complex numbers to collect the information contained in the system…

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

We present an efficient implementation of Wiener filtering of real-space linear field and optimal quadratic estimator of its power spectrum Band-powers. We first recast the field reconstruction into an optimization problem, which we solve…

Cosmology and Nongalactic Astrophysics · Physics 2019-10-16 Benjamin Horowitz , Uros Seljak , Grigor Aslanyan

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 explore two methods of compressing the redshift space galaxy power spectrum and bispectrum with respect to a chosen set of cosmological parameters. Both methods involve reducing the dimension of the original data-vector ( e.g. 1000…

Cosmology and Nongalactic Astrophysics · Physics 2018-01-31 Davide Gualdi , Marc Manera , Benjamin Joachimi , Ofer Lahav

Weak gravitational lensing surveys have the potential to directly probe mass density fluctuation in the universe. Recent studies have shown that it is possible to model the statistics of the convergence field at small angular scales by…

Astrophysics · Physics 2008-11-26 Dipak Munshi , Bhuvnesh Jain

Spectral line intensity mapping has been proposed as a promising tool to efficiently probe the cosmic reionization and the large-scale structure. Without detecting individual sources, line intensity mapping makes use of all available…

Cosmology and Nongalactic Astrophysics · Physics 2016-12-14 Yun-Ting Cheng , Tzu-Ching Chang , James Bock , C. Matt Bradford , Asantha Cooray

Modelling of the weak lensing of the CMB will be crucial to obtain correct cosmological parameter constraints from forthcoming precision CMB anisotropy observations. The lensing affects the power spectrum as well as inducing…

Astrophysics · Physics 2010-11-17 Antony Lewis

Redshift evolution and peculiar velocities break the isotropy of cosmological surveys with respect to the directions parallel and transverse to the line of sight, limiting the accuracy of the Fourier representation to small areas and…

Cosmology and Nongalactic Astrophysics · Physics 2022-09-21 L. Raul Abramo , João Ferri , Ian Tashiro , Arthur Loureiro

This paper generalises the hybrid power spectrum estimator developed in Efstathiou (2004a) to the estimation of polarization power spectra of the cosmic microwave background radiation. The hybrid power spectrum estimator is unbiased and we…

Astrophysics · Physics 2009-11-11 G. Efstathiou

Based on realistic simulations, we propose an hybrid method to reconstruct the lensing potential power spectrum, directly on PLANCK-like CMB frequency maps. It implies using a large galactic mask and dealing with a strong inhomogeneous…

Cosmology and Nongalactic Astrophysics · Physics 2015-03-20 S. Plaszczynski , A. Lavabre , L. Perotto , J. -L. Starck

A comprehensive convergence and stability analysis of some probabilistic numerical methods designed to solve Cauchy-type inverse problems is performed in this study. Such inverse problems aim at solving an elliptic partial differential…

Numerical Analysis · Mathematics 2025-08-12 Iulian Cîmpean , Andreea Grecu , Liviu Marin

The reconstruction of the CMBR power spectrum from a map represents a major computational challenge to which much effort has been applied. However, once the power spectrum has been recovered there still remains the problem of extracting…

Astrophysics · Physics 2009-12-30 Steen Hannestad

Cosmic microwave background studies of non-Gaussianity involving higher-order multispectra can distinguish between early universe theories that predict nearly identical power spectra. However, the recovery of higher-order multispectra is…

Cosmology and Nongalactic Astrophysics · Physics 2011-07-26 Dipak Munshi , Alan Heavens , Asantha Cooray , Joseph Smidt , Peter Coles , Paolo Serra

We study theoretically inelastic spectrum of coherent backscattering of laser light by two atoms. For an intense laser field, there are frequency domains of not only constructive but also destructive (self-)interference of the inelastic…

Quantum Physics · Physics 2009-11-13 Vyacheslav Shatokhin
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