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The "dark flow" dipole is a statistically significant dipole found at the position of galaxy clusters in filtered maps of Cosmic Microwave Background (CMB) temperature anisotropies. The dipole measured in WMAP 3, 5 and 7 yr data releases…

宇宙学与河外天体物理 · 物理学 2015-09-23 Fernando Atrio-Barandela , Alexander Kashlinsky , Harald Ebeling , Dale J. Fixsen , Dale Kocevski

We repeat and extend the analysis of Eriksen et al 2004 and Hansen et al 2004 testing the isotropy of the Cosmic Microwave Background (CMB) fluctuations. We find that the hemispherical power asymmetry previously reported for the largest…

天体物理学 · 物理学 2014-11-18 F. K. Hansen , A. J. Banday , K. M. Gorski , H. K. Eriksen , P. B. Lilje

We theoretically analyze the dipole anisotropy observed in the quasar distribution from the CatWISE2020 catalog. The catalog data shows a peak around $z\approx 1$, suggesting the presence of a large-scale dipole component. We explore the…

宇宙学与河外天体物理 · 物理学 2025-10-16 Gopal Kashyap , Naveen K. Singh , Pankaj Jain

We search for planar deviations of statistical isotropy in the Wilkinson Microwave Anisotropy Probe (WMAP) data by applying a recently introduced angular-planar statistics both to full-sky and to masked temperature maps, including in our…

宇宙学与河外天体物理 · 物理学 2014-11-20 L. Raul Abramo , Armando Bernui , Thiago S. Pereira

A recent analysis of data collected by the Planck satellite detected a net dipole at the location of X-ray selected galaxy clusters, corresponding to a large-scale bulk flow extending at least to $z\sim 0.18$, the median redshift of the…

宇宙学与河外天体物理 · 物理学 2015-06-15 F. Atrio-Barandela

We derive a general expression for the probability of observing deviations from statistical isotropy in the cosmic microwave background (CMB) if the primordial fluctuations are non-Gaussian and extend to superhorizon scales. The primary…

宇宙学与河外天体物理 · 物理学 2016-01-27 Saroj Adhikari , Sarah Shandera , Adrienne L. Erickcek

A recent study of the rotation of the plane of polarization of light from 160 cosmological sources claims to find significant evidence for cosmological anisotropy. We point out methodological weaknesses of that study, and reanalyze the same…

天体物理学 · 物理学 2009-12-30 Thomas J. Loredo , Eanna E. Flanagan , Ira M. Wasserman

We use linear estimators to determine the magnitude and direction of the cosmic radio dipole from the NRAO VLA Sky Survey (NVSS) and the Westerbork Northern Sky Survey (WENSS). We show that special attention has to be given to the issues of…

宇宙学与河外天体物理 · 物理学 2013-07-25 Matthias Rubart , Dominik J. Schwarz

In both WMAP and Planck observations on the temperature anisotropy of cosmic microwave background (CMB) radiation a number of large-scale anomalies were discovered in the past years, including the CMB parity asymmetry in the low multipoles.…

宇宙学与河外天体物理 · 物理学 2017-08-22 Wen Zhao , Larissa Santos

We report the results of a statistical analysis performed with the four foreground-cleaned Planck maps by means of a suitably defined {\it local-variance} estimator. Our analysis shows a clear dipolar structure in Planck's {\it variance…

宇宙学与河外天体物理 · 物理学 2014-10-17 A. Bernui , A. F. Oliveira , T. S. Pereira

The direction dependence of the WIMP direct detection rate provides a powerful tool for distinguishing a WIMP signal from possible backgrounds. We study the the number of events required to discriminate a WIMP signal from an isotropic…

天体物理学 · 物理学 2009-11-13 Ben Morgan , Anne M. Green

We probe the statistical isotropy hypothesis of the large-scale structure with the second Planck Sunyaev-Zeldovich (PSZ2) galaxy clusters data set. Our analysis adopts a statistical-geometrical method which compares the 2-point angular…

宇宙学与河外天体物理 · 物理学 2016-12-15 C. A. P. Bengaly , A. Bernui , I. S. Ferreira , J. S. Alcaniz

We argue that the observed large-scale cosmic microwave anomalies, discovered by WMAP and confirmed by the Planck satellite, are most naturally explained in the context of a marginally-open universe. Particular focus is placed on the dipole…

宇宙学与河外天体物理 · 物理学 2014-11-05 Andrew R Liddle , Marina Cortês

Recently a symmetry-based method to test for statistical isotropy of the cosmic microwave background was developed. We apply the method to template-cleaned 3-year and 5-year WMAP-$DA$ maps. We examine a wide range of angular multipoles from…

天体物理学 · 物理学 2010-11-02 Pramoda Kumar Samal , Rajib Saha , Pankaj Jain , John P. Ralston

A linear modulation of the primordial perturbations is proposed as an explanation for the observed asymmetry between the northern and southern hemispheres of the Wilkinson Microwave Anisotropy Probe (WMAP) data. A cut sky, reduced…

天体物理学 · 物理学 2008-11-26 Christopher Gordon

Recent Wilkinson Microwave Anisotropy Probe (WMAP) data confirm the Cosmic Microwave Background (CMB) quadrupole anomaly. We further elaborate our previous proposal that the quadrupole power can be naturally suppressed in axis-symmetric…

天体物理学 · 物理学 2008-11-26 L. Campanelli , P. Cea , L. Tedesco

In this study we investigate potential large-angle anisotropies in the angular distribution of the cosmological parameters $H_0$ (the Hubble constant) and $\Omega_m$ (the matter density) in the flat-$\Lambda$CDM framework, using the…

宇宙学与河外天体物理 · 物理学 2025-12-08 Rahima Mokeddem , Maria Lopes , Felipe Avila , Armando Bernui , Wiliam S. Hipólito-Ricaldi

The Cold Spot (CS) is a clear feature in the Cosmic Microwave Background (CMB); it could be of primordial origin, or caused by a intervening structure along the line of sight. We identified a large projected underdensity in the recently…

宇宙学与河外天体物理 · 物理学 2017-03-22 Fabio Finelli , Juan Garcia-Bellido , Andras Kovacs , Francesco Paci , Istvan Szapudi

The number counts of homogeneous samples of radio sources are a tried and true method of probing the large scale structure of the Universe, as most radio sources outside the galactic plane are at cosmological distances. As such they are…

Anisotropic cosmological models have been gaining attention due to various observational hints of large-scale anisotropies. One of the most surprising evidences for the latter is the discovery of a dipole-like directional variation in…

宇宙学与河外天体物理 · 物理学 2025-08-08 Boris Hoi-Lun Ng , Ming-Chung Chu