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相关论文: Examining statistical isotropy of CMB low multipol…

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Unexpected features have been observed in the cosmic microwave background (CMB) temperature on large scales. We revisit these CMB anomalies using new foreground-cleaned CMB temperature maps derived in a companion paper from WMAP and Planck…

宇宙学与河外天体物理 · 物理学 2025-09-05 Laura Herold , Graeme E. Addison , Charles L. Bennett , Hayley C. Nofi , J. L. Weiland

Measurements of the cosmic microwave background (CMB) radiation provide a unique opportunity for a direct study of the primordial cosmic plasma at redshift z ~1000. The angular power spectra of temperature and polarisation fluctuations are…

天体物理学 · 物理学 2009-11-10 Marco Bersanelli , Davide Maino , Aniello Mennella

We introduce new symmetry-based methods to test for isotropy in cosmic microwave background radiation. Each angular multipole is factored into unique products of power eigenvectors, related multipoles and singular values that provide 2 new…

天体物理学 · 物理学 2008-11-26 Pramoda Kumar Samal , Rajib Saha , Pankaj Jain , John P. Ralston

Measurements of the cosmic microwave background (CMB) allow high precision observation of the cosmic plasma at redshift z~1100. After the success of the NASA satellite COBE, that in 1992 provided the first detection of the CMB anisotropy,…

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…

天体物理学 · 物理学 2007-05-23 Amir Hajian

In this article we propose a novel test for statistical anisotropy of the CMB. The test is based on the fact, that the Galactic foregrounds have a remarcably strong symmetry with respect to their antipodal points and with respect to the…

宇宙学与河外天体物理 · 物理学 2015-05-28 P. Naselsky , M. Hansen , J. Kim

Several statistical anomalies in the CMB temperature anisotropies seem to defy the assumption of a homogeneous and isotropic universe. In particular, a dipole modulation has been detected both in WMAP and Planck data. We adapt the…

宇宙学与河外天体物理 · 物理学 2014-07-29 R. Fernández-Cobos , P. Vielva , D. Pietrobon , A. Balbi , E. Martínez-González , R. B. Barreiro

The statistical expectation values of the temperature fluctuations of cosmic microwave background (CMB) are assumed to be preserved under rotations of the sky. We investigate the statistical isotropy of the CMB anisotropy maps recently…

天体物理学 · 物理学 2007-05-23 Tarun Souradeep , Amir Hajian

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

Search for the statistical anisotropy in the CMB data is a powerful tool for constraining models of the early Universe. In this paper we focus on the recently proposed cosmological scenario with conformal rolling. We consider two…

宇宙学与河外天体物理 · 物理学 2015-06-04 S. R. Ramazanov , G. I. Rubtsov

The Microwave Anisotropy Probe and Planck missions will provide low noise maps of the temperature of the cosmic microwave background (CMB). These maps will allow measurement of the power spectrum of the CMB with measurement noise below…

The lack of power at large angular scales in the CMB temperature anisotropy pattern is a feature known to depend on the size of the Galactic mask. Not only the large scale anisotropy power in the CMB is lower than the best-fit $\Lambda$CDM…

宇宙学与河外天体物理 · 物理学 2020-03-11 U. Natale , A. Gruppuso , D. Molinari , P. Natoli

Gaussianity and statistical isotropy of the Universe are modern cosmology's minimal set of hypotheses. In this work we introduce a new statistical test to detect observational deviations from this minimal set. By defining the temperature…

宇宙学与河外天体物理 · 物理学 2009-09-30 Thiago S. Pereira , L. Raul Abramo

Analyses of recent cosmic microwave background (CMB) observations have provided increasing indications for the existence of large scale anisotropy in the universe. Given the far reaching consequences of such an anisotropy for our…

天体物理学 · 物理学 2009-09-29 A. Bernui , B. Mota , M. J. Reboucas , R. Tavakol

The cosmic microwave background (CMB) temperature and polarization anisotropies, as observed by independent astronomical missions such as WMAP, Planck, and most recently the Atacama Cosmology Telescope and the South Pole Telescope have…

宇宙学与河外天体物理 · 物理学 2023-09-13 William Giarè , Supriya Pan , Eleonora Di Valentino , Weiqiang Yang , Jaume de Haro , Alessandro Melchiorri

The remarkable progress in cosmic microwave background (CMB) studies over past decade has led to the era of precision cosmology in striking agreement with the $\Lambda$CDM model. However, the lack of power in the CMB temperature…

宇宙学与河外天体物理 · 物理学 2015-06-09 Asif Iqbal , Jayanti Prasad , Tarun Souradeep , Manzoor A. Malik

The large-angular-scale falloff in the autocorrelation function for the cosmic microwave background (CMB) temperature has long intrigued cosmologists and fueled speculation about suppressed superhorizon power. Here we highlight an…

宇宙学与河外天体物理 · 物理学 2023-11-13 Jahmour J. Givans , Marc Kamionkowski

We study the power asymmetry between even and odd multipoles in the multipolar expansion of CMB temperature data from WMAP, recently reported in the literature. We introduce an alternate statistic which probes this effect more sensitively.…

宇宙学与河外天体物理 · 物理学 2012-12-04 Pavan K. Aluri , Pankaj Jain

The angular power spectra of the cosmic microwave background (CMB) temperature anisotropies reconstructed from Planck data seem to present too much gravitational lensing distortion. This is quantified by the control parameter $A_L$ that…

宇宙学与河外天体物理 · 物理学 2017-01-18 F. Couchot , S. Henrot-Versillé , O. Perdereau , S. Plaszczynski , B. Rouillé d'Orfeuil , M. Spinelli , M. Tristram

Large-scale magnetic fields affect the scalar modes of the geometry whose ultimate effect is to determine the anisotropies of the Cosmic Microwave Background (CMB in what follows). For the first time, a consistent numerical approach to the…

天体物理学 · 物理学 2010-04-29 Massimo Giovannini , Kerstin E. Kunze