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We revisit the alignments of the largest structures observed in the cosmic microwave background (CMB) using the seven and nine-year WMAP and first-year Planck data releases. The observed alignments -- the quadrupole with the octopole and…

宇宙学与河外天体物理 · 物理学 2015-06-04 Craig J. Copi , Dragan Huterer , Dominik J. Schwarz , Glenn D. Starkman

In this paper, we study the anisotropy of cosmic acceleration by dividing the Union2 Type Ia supernova dataset into 12 subsets according to their positions in Galactic coordinate system. In each region, we derive the deceleration parameter…

宇宙学与河外天体物理 · 物理学 2013-06-17 W. Zhao , P. X. Wu , Y. Zhang

Traditional view of the anomalous Hall effect~(AHE) in ferromagnets is that it arises from the magnetization perpendicular to the measurement plane and that there is a linear dependence on the latter. Underlying such a view is the thinking…

材料科学 · 物理学 2024-08-19 Zheng Liu , Mengjie Wei , Dazhi Hou , Yang Gao , Qian Niu

We extend the previously described CMB Gibbs sampling framework to allow for exact Bayesian analysis of anisotropic universe models, and apply this method to the 5-year WMAP temperature observations. This involves adding support for…

天体物理学 · 物理学 2011-02-11 Nicolaas E. Groeneboom , Hans Kristian Eriksen

Cosmic microwave background measurements show an agreement with the concordance cosmology model except for a few notable anomalies: Power Suppression, the lack of large scale power in the temperature data compared to what is expected in the…

宇宙学与河外天体物理 · 物理学 2019-08-20 Shabbir Shaikh , Suvodip Mukherjee , Santanu Das , Benjamin D. Wandelt , Tarun Souradeep

Observations show that the Cosmic Microwave Background (CMB) contains tiny variations at the 10^{-5} level around its black-body equilibrium temperature. The detection of these temperature fluctuations provides to modern Cosmology evidence…

天体物理学 · 物理学 2015-06-24 Armando Bernui

We question the global universe isotropy by probing the alignment of local structures in the cosmic microwave background (CMB) radiation. The original method proposed relies on a steerable wavelet decomposition of the CMB signal on the…

天体物理学 · 物理学 2007-05-23 Y. Wiaux , P. Vielva , E. Martinez-Gonzalez , P. Vandergheynst

We reconsider analysis of data on the cosmic microwave background on the largest angular scales. Temperature multipoles of any order factor naturally into a direct product of axial quantities and cosets. Striking coincidences exist among…

天体物理学 · 物理学 2011-09-13 John P. Ralston , Pankaj Jain

Context. The existence of a maximum correlation angle ($\theta_{max} \gtrsim 60^{\circ}$) in the two-point angular temperature correlations of cosmic microwave background (CMB) radiation, measured by WMAP and Planck, stands in sharp…

宇宙学与河外天体物理 · 物理学 2022-04-27 M. -A. Sanchis-Lozano , F. Melia , M. López-Corredoira , N. Sanchis-Gual

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

We use a global pixel based estimator to identify the axis of the residual Maximum Temperature Asymmetry (MTA) (after the dipole subtraction) of the WMAP 7 year Internal Linear Combination (ILC) CMB temperature sky map. The estimator is…

宇宙学与河外天体物理 · 物理学 2013-05-30 Antonio Mariano , Leandros Perivolaropoulos

Noticeable deviations from the prediction of the fiducial LCDM cosmology are found in the angular power spectrum of the CMB. Besides large-angle anomalies, the WMAP 1st year data revealed a dip in the power spectrum at l \sim 200, which…

宇宙学与河外天体物理 · 物理学 2011-05-12 Amanda Yoho , Francesc Ferrer , Glenn D. Starkman

Anomalies of the cosmic microwave background (CMB) maps have been widely acquainted nowadays from the Wilkinson Microwave Anisotropy Probe (WMAP) satellite to the Planck satellite. One of the anomalies is a multipole alignment from $l=2$ to…

高能天体物理现象 · 物理学 2014-06-30 Lixiong Gan , Yuan-Chuan Zou , Zi-Gao Dai

We investigate the large scale anomalies in the angular distribution of the cosmic microwave background radiation as measured by WMAP using several tests. These tests, based on the multipole vector expansion, measure correlations between…

天体物理学 · 物理学 2009-08-19 L. Raul Abramo , Armando Bernui , Ivan S. Ferreira , T. Villela , C. Alexandre Wuensche

The origin of power asymmetry and other measures of statistical anisotropy on the largest scales of the universe, as manifested in Cosmic Microwave Background (CMB) and large-scale structure data, is a long-standing open question in…

宇宙学与河外天体物理 · 物理学 2021-05-12 Pablo Fosalba , Enrique Gaztanaga

We present a determination of the cosmic microwave background dipole amplitude and direction from the COBE Differential Microwave Radiometers (DMR) first year of data. Data from the six DMR channels are consistent with a Doppler-shifted…

天体物理学 · 物理学 2009-10-22 A. Kogut , C. Lineweaver , G. F. Smoot , C. L. Bennett , A. Banday

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

We investigate the Statistical Isotropy and Gaussianity of the CMB fluctuations, using a set of multipole vector functions capable of separating these two issues. In general a multipole is broken into a frame and $2\ell-3$ ordered…

天体物理学 · 物理学 2008-11-26 Kate Land , Joao Magueijo

We revisit the anisotropic universe model previously developed by Ackerman, Carroll and Wise (ACW), and generalize both the theoretical and computational framework to include polarization and various forms of systematic effects. We apply…

宇宙学与河外天体物理 · 物理学 2014-11-20 Nicolaas E. Groeneboom , Lotty Ackerman , Ingunn Kathrine Wehus , Hans Kristian Eriksen

(Abridged)Motivated by the recent results of Hansen et al. (2008) concerning a noticeable hemispherical power asymmetry in the WMAP data on small angular scales, we revisit the dipole modulated signal model introduced by Gordon et al.…

宇宙学与河外天体物理 · 物理学 2011-02-11 J. Hoftuft , H. K. Eriksen , A. J. Banday , K. M. Gorski , F. K. Hansen , P. B. Lilje