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Low multipoles ($l$) in cosmic microwave background (CMB) temperature anisotropies have shown some `peculiarities' when examined since the release of the full sky CMB maps, using a variety of tests. In this paper, we concern ourselves with…

宇宙学与河外天体物理 · 物理学 2025-07-01 Pavan Kumar Aluri , Sanjeet Kumar Patel

Using the formalism of spin-weighted functions we present an all-sky analysis of polarization in the Cosmic Microwave Background (CMB). Linear polarization is a second-rank symmetric and traceless tensor, which can be decomposed on a sphere…

天体物理学 · 物理学 2009-10-28 Matias Zaldarriaga , Uros Seljak

We study the position estimation of a mechanical oscillator undergoing both detuned parametric amplification and continuous quantum measurement. This model, which can be utilised to produce squeezed states, is applied to a general…

量子物理 · 物理学 2012-10-01 Alex Szorkovszky , Andrew C. Doherty , Glen I. Harris , Warwick P. Bowen

In addition to shear and vorticity a homogeneous background may also exhibit anisotropic curvature. Here a class of spacetimes is shown to exist where the anisotropy is solely of the latter type, and the shear-free condition is supported by…

宇宙学与河外天体物理 · 物理学 2011-02-02 Tomi S. Koivisto , David F. Mota , Miguel Quartin , Tom G. Zlosnik

We explore the reconstruction of the gravitational lensing field of the cosmic microwave background in real space showing that very little statistical information is lost when estimators of short range on the celestial sphere are used in…

宇宙学与河外天体物理 · 物理学 2013-05-30 Martin Bucher , Carla Sofia Carvalho , Kavilan Moodley , Mathieu Remazeilles

Future experiments will produce high-resolution temperature maps of the cosmic microwave background (CMB) and are expected to reveal the signature of gravitational lensing by intervening large-scale structures. We construct all-sky…

天体物理学 · 物理学 2009-11-07 Christopher M. Hirata , Uros Seljak

Airspace sectorisation provides a partition of a given airspace into sectors, subject to geometric constraints and workload constraints, so that some cost metric is minimised. We survey the algorithmic aspects of methods for automatic…

其他计算机科学 · 计算机科学 2013-11-05 Pierre Flener , Justin Pearson

A persistent signal of power asymmetry on opposite hemispheres of CMB sky was seen in full-sky temperature measurements made so far. This asymmetry was seen in microwave sky from WMAP as well as PLANCK satellites, and calls for attention…

宇宙学与河外天体物理 · 物理学 2017-10-03 Pavan K. Aluri , Arman Shafieloo

The presence of matter in the path of relic photons causes distortions in the angular pattern of the cosmic microwave background (CMB) temperature fluctuations, modifying their properties in a slight but measurable way. Recently, the Planck…

宇宙学与河外天体物理 · 物理学 2017-09-11 G. A. Marques , C. P. Novaes , A. Bernui , I. S. Ferreira

Beam asymmetries result in statistically-anisotropic cosmic microwave background (CMB) maps. Typically, they are studied for their effects on the CMB power spectrum, however they more closely mimic anisotropic effects such as gravitational…

宇宙学与河外天体物理 · 物理学 2010-10-05 Duncan Hanson , Antony Lewis , Anthony Challinor

The paper addresses the stabilization of nonlinear systems with semi-quadratic cost: quadratic with respect to controls and nonlinear for state variables. Paper presents the effective new feedback synthesis procedure. The novel feedback…

最优化与控制 · 数学 2008-01-31 S. Nikitin

Despite the fact that the physics of the cosmic microwave background anisotropies is most naturally expressed in Fourier space, pixelised maps are almost always used in the analysis and simulation of microwave data. A complementary approach…

We derive optimal estimators for the two-, three-, and four-point correlators of statistically isotropic scalar fields defined on the sphere, such as the Cosmic Microwave Background temperature fluctuations, allowing for arbitrary (linear)…

宇宙学与河外天体物理 · 物理学 2023-06-28 Oliver H. E. Philcox

The Quadratic Maximum Likelihood estimator can be used to reconstruct the Cosmic Microwave Background (CMB) power spectra with minimal error bars. Still, it requires an accurate estimate of the datasets noise covariance matrix in order to…

宇宙学与河外天体物理 · 物理学 2018-11-28 S. Vanneste , S. Henrot-Versillé , T. Louis , M. Tristram

We consider the benefits of measuring cosmic statistical anisotropy from redshift-space correlators of the galaxy number density fluctuation and the peculiar velocity field without adopting the plane-parallel (PP) approximation. Since the…

宇宙学与河外天体物理 · 物理学 2021-03-17 Maresuke Shiraishi , Teppei Okumura , Kazuyuki Akitsu

We compute the reduced cosmic shear up to second order in the gravitational potential without relying on the small angle or thin-lens approximation. This is obtained by solving the Sachs equation which describes the deformation of the…

宇宙学与河外天体物理 · 物理学 2010-04-14 Francis Bernardeau , Camille Bonvin , Filippo Vernizzi

The statistical properties of the temperature anisotropies and polarization of the of cosmic microwave background (CMB) radiation offer a powerful probe of the physics of the early universe. In recent works a statistical procedure based…

宇宙学与河外天体物理 · 物理学 2017-03-15 M. J. Reboucas , A. Bernui

A spatial point pattern is called anisotropic if its spatial structure depends on direction. Several methods for anisotropy analysis have been introduced in the literature. In this paper, we give an overview of nonparametric methods for…

统计方法学 · 统计学 2018-03-01 Tuomas Rajala , Claudia Redenbach , Aila Särkkä , Martina Sormani

We consider several factors concerning the design of observing strategies in Cosmic Microwave Background (CMB) anisotropy experiments. First we consider the number of independent points on the sky one should observe given a fixed observing…

天体物理学 · 物理学 2007-05-23 R. K. Schaefer , L. Piccirillo

This is a review of the theory of CMB anisotropies, an updated version of a course given at the troisieme cycle de la Suisse Romande. An introduction to gauge invariant cosmological perturbation theory is given and the theory CMB…

天体物理学 · 物理学 2014-10-13 Ruth Durrer