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Precise reconstruction of the cosmic microwave background lensing potential can be achieved with deep polarization surveys by iteratively removing lensing-induced $B$ modes. We introduce a lensing spectrum estimator and its likelihood for…

Cosmology and Nongalactic Astrophysics · Physics 2022-12-13 Louis Legrand , Julien Carron

As the era of high precision cosmology approaches, the empirically determined power spectrum of the microwave background anisotropy, $C_l$, will provide a crucial test for cosmological theories. We present a unified semi-analytic framework…

Astrophysics · Physics 2009-10-30 Benjamin D. Wandelt , Eric Hivon , Krzysztof M. Gorski

We investigate large-angle scale temperature anisotropy in the Cosmic Microwave Background (CMB) with the Wilkinson Microwave Anisotropy Probe (WMAP) data and model the large-angle anomalies as the effect of the CMB quadrupole anisotropies…

Cosmology and Nongalactic Astrophysics · Physics 2014-11-20 Li-Ping He , Quan Guo

The lack of power anomaly is an intriguing feature at the largest angular scales of the CMB anisotropy temperature pattern, whose statistical significance is not strong enough to claim any new physics beyond the standard cosmological model.…

Cosmology and Nongalactic Astrophysics · Physics 2019-06-11 M. Billi , A. Gruppuso , N. Mandolesi , L. Moscardini , P. Natoli

Microwave background temperature and polarization observations are a powerful way to constrain cosmological parameters if the likelihood function can be calculated accurately. The temperature and polarization fields are correlated, partial…

Astrophysics · Physics 2012-04-25 Samira Hamimeche , Antony Lewis

This paper deals with subspace estimation in the small sample size regime, where the number of samples is comparable in magnitude with the observation dimension. The traditional estimators, mostly based on the sample correlation matrix, are…

Methodology · Statistics 2015-06-19 Pascal Vallet , Xavier Mestre , Philippe Loubaton

The Cosmology Large Angular Scale Surveyor (CLASS) is mapping the polarization of the Cosmic Microwave Background (CMB) at large angular scales ($2<\ell\lesssim200$) in search of a primordial gravitational wave B-mode signal down to a…

The scalar mode temperature fluctuations of the cosmic microwave background has been derived in a spatially closed universe from two different methods. First, by following the photon trajectory after the last scattering and then from the…

General Relativity and Quantum Cosmology · Physics 2017-09-27 Pedram Niazy , Amir H. Abbassi

We review and compare two different CMB dipole estimators discussed in the literature, and assess their performances through Monte Carlo simulations. The first method amounts to simple template regression with partial sky data, while the…

Cosmology and Nongalactic Astrophysics · Physics 2020-11-25 H. Thommesen , K. J. Andersen , R. Aurlien , R. Banerji , M. Brilenkov , H. K. Eriksen , U. Fuskeland , M. Galloway , L. M. Mocanu , T. L. Svalheim , I. K. Wehus

This paper presents a feasibility study demonstrating that quantum machine learning (QML) algorithms achieve competitive performance on real-world medical imaging despite operating under severe constraints. We evaluate Equilibrium…

Emerging Technologies · Computer Science 2026-01-27 A. Bano , L. Liebovitch

In many spatial and spatial-temporal models, and more generally in models with complex dependencies, it may be too difficult to carry out full maximum likelihood (ML) analysis. Remedies include the use of pseudo-likelihood (PL) and…

Methodology · Statistics 2026-04-24 Nils Lid Hjort , Cristiano Varin

We show that the popular ILC approach is unstable in respect to the division of the sample of map pixels to the set of ``homogeneous'' subsamples. For suitable choice of such subsamples we can obtain the restored CMB signal with amplitudes…

Cosmology and Nongalactic Astrophysics · Physics 2011-02-18 A. Doroshkevich , O. Verkhodanov

In this work, we formalize a new technique to investigate joint posterior density of Cosmic Microwave Background (CMB) signal and its theoretical angular power spectrum given the observed data, using the global internal-linear-combination…

Cosmology and Nongalactic Astrophysics · Physics 2018-10-23 Vipin Sudevan , Rajib Saha

The cosmic microwave background (CMB) is gravitationally lensed by large-scale structure, which distorts observations of the primordial anisotropies in any given direction. Averaged over the sky, this important effect is routinely modelled…

Cosmology and Nongalactic Astrophysics · Physics 2021-03-17 G. Fabbian , J. Carron , A. Lewis , M. Lembo

The low quadrupole of the cosmic microwave background (CMB), measured by COBE and confirmed by WMAP, has generated much discussion recently. We point out that the well-known correlation between temperature and polarization anisotropies of…

Astrophysics · Physics 2009-06-15 Olivier Doré , Gilbert P. Holder , Abraham Loeb

We extend the pure pseudo-power-spectrum formalism proposed recently in the context of the Cosmic Microwave Background polarized power spectra estimation by Smith (2006) to incorporate cross-spectra computed for multiple maps of the same…

Cosmology and Nongalactic Astrophysics · Physics 2009-07-09 J. Grain , M. Tristram , R. Stompor

Various data analyses of the Cosmic Microwave Background (CMB) provide observational hints of statistical isotropy breaking. Some of these features can be studied within the framework of primordial vector fields in inflationary theories…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-28 N. Bartolo , E. Dimastrogiovanni , M. Liguori , S. Matarrese , A. Riotto

Some peculiar features found in the angular distribution of the cosmic microwave background (CMB) measured by the Wilkinson Microwave Anisotropy Probe (WMAP) deserve further investigation. Among these peculiar features, is the quadrant…

Cosmology and Nongalactic Astrophysics · Physics 2014-10-01 Larissa Santos , Paolo Cabella , Thyrso Villela , Amedeo Balbi , Nicola Vittorio , Carlos Alexandre Wuensche

The Cosmic Microwave Background (CMB) reaches homogeneity at relatively modest angular scales compared to the expectation of the standard $\Lambda$CDM model revealing an important challenge to the theoretical predictions. We analyze this…

We use simulated maps of the cosmic microwave background anisotropy to quantify the ability of different statistical tests to discriminate between Gaussian and non-Gaussian models. Despite the central limit theorem on large angular scales,…

Astrophysics · Physics 2009-10-31 Nicholas G. Phillips , A. Kogut
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