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Several analyses of the microwave sky maps from the Wilkinson Microwave Anisotropy Probe (WMAP) have drawn attention to alignments amongst the low-order multipoles. Amongst the various possible explanations, an effect of cosmic topology has…

Astrophysics · Physics 2009-11-13 James G. Cresswell , Andrew R. Liddle , Pia Mukherjee , Alain Riazuelo

A previous work (Monteser\'in et al. 2008) estimated the CMB variance from the three-year WMAP data, finding a lower value than expected from Gaussian simulations using the WMAP best-fit cosmological model. We repeat the analysis on the…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-18 M. Cruz , P. Vielva , E. Martínez-González , R. B. Barreiro

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

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…

The quadrupole power of cosmic microwave background (CMB) temperature anisotropies seen in the WMAP data is puzzlingly low. In this paper we demonstrate that Minimum Variance Optimization (MVO), a technique used by many authors (including…

Astrophysics · Physics 2009-03-18 Lung-Yih Chiang , Pavel D. Naselsky , Peter Coles

The dipolar model \cite{Gordon:2005ai} has attracted much interest because it may phenomenologically explain the CMB hemispherical power asymmetry found in the WMAP and Planck data. Since such a model explicitly breaks isotropy at large…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-24 L. Polastri , A. Gruppuso , P. Natoli

The low multipoles of the cosmic microwave background (CMB) anisotropy possess some strange properties like the alignment of the quadrupole and the octopole, and the extreme planarity or the extreme sphericity of some multipoles,…

Astrophysics · Physics 2008-11-26 R. Aurich , S. Lustig , F. Steiner , H. Then

The largest uncollapsed inhomogeneity in the observable Universe is statistically represented in the quadrupole signal of the cosmic microwave background (CMB) sky maps as observed by the Wilkinson Microwave Anisotropy Probe (WMAP). The…

Cosmology and Nongalactic Astrophysics · Physics 2010-08-09 Boudewijn F. Roukema

We have investigated the constraints on the Cardassian model using the recent results from the Wilkinson Microwave Anisotropy Probe (WMAP) for the locations of the peaks of the Cosmic Microwave Background (CMB) anistropy spectrum. We find…

Astrophysics · Physics 2016-08-30 A. A. Sen , S. Sen

We constrain several models of the early Universe that predict a statistical anisotropy of the cosmic microwave background (CMB) sky. We make use of WMAP9 maps deconvolved with beam asymmetries. As compared to previous releases of WMAP…

Cosmology and Nongalactic Astrophysics · Physics 2014-03-03 Sabir Ramazanov , Grigory Rubtsov

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…

The first observations of the cosmic microwave background (CMB) from NASA's \emph{Wilkinson Microwave Anisotropy Probe} (WMAP) led to finding `alignment' anomalies not expected from fluctuations in the isotropic cosmological model. We study…

Cosmology and Nongalactic Astrophysics · Physics 2025-06-03 Sanjeet Kumar Patel , Pavan Kumar Aluri , John P. Ralston

We present the temperature and polarization angular power spectra of the cosmic microwave background (CMB) derived from the first 5 years of WMAP data. The 5-year temperature (TT) spectrum is cosmic variance limited up to multipole l=530,…

[Abridged] We apply the multipole vector framework to full-sky maps derived from the first year WMAP data. We significantly extend our earlier work showing that the two lowest cosmologically interesting multipoles, l=2 and 3, are not…

Astrophysics · Physics 2009-11-11 C. J. Copi , D. Huterer , D. J. Schwarz , G. D. Starkman

We study the alignments of the low multipoles of CMB anisotropies with specific directions in the sky (i.e. the dipole, the north Ecliptic pole, the north Galactic pole and the north Super Galactic pole). Performing $10^5$ random…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-18 Alessandro Gruppuso , Krzysztof M. Gorski

(Abridged) A simple six-parameter LCDM model provides a successful fit to WMAP data, both when the data are analyzed alone and in combination with other cosmological data. Even so, it is appropriate to search for any hints of deviations…

We present a CMB temperature power spectrum measurement at large angular scales from WMAP and Planck maps that were cleaned of foregrounds using a template-based approach described in a companion paper. We recover essentially the full-sky…

Cosmology and Nongalactic Astrophysics · Physics 2025-09-05 Hayley C. Nofi , Graeme E. Addison , Charles L. Bennett , Laura Herold , J. L. Weiland

We study the apparent lack of power on large angular scales in the WMAP data. We confirm that although there is no apparent lack of power at large angular scales for the full-sky maps, the lowest multipoles of the WMAP data happen to have…

Astrophysics · Physics 2007-05-23 Amir Hajian

Recent analyses of the cosmic microwave background (CMB) maps from the WMAP satellite have uncovered evidence for a hemispherical power anomaly, i.e. a dipole modulation of the CMB power spectrum at large angular scales with an amplitude of…

Cosmology and Nongalactic Astrophysics · Physics 2009-09-28 Christopher M. Hirata

We revisit the degeneracy between the Hubble constant, $H_0$, and matter density, $\Omega_m$, for current cosmic microwave background (CMB) observations within the standard $\Lambda CDM$ model. We show that Planck, Wilkinson Microwave…

Cosmology and Nongalactic Astrophysics · Physics 2021-01-26 Joshua A. Kable , Graeme E. Addison , Charles L. Bennett