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We investigate the imprint of nonlinear matter condensations on the Cosmic Microwave Background (CMB) in an $\Omega=1$, Cold Dark Matter (CDM) model universe. Temperature anisotropies are obtained by numerically evolving matter…

天体物理学 · 物理学 2016-08-30 Robin Tuluie , Pablo Laguna

We are in motion against the cosmic backdrop. This motion is evidenced by the systematic temperature shift - or dipole anisotropy - observed in the Cosmic Microwave Background radiation (CMB). Because of the Doppler effect, the temperature…

天体物理学 · 物理学 2015-06-24 Chris Blake , Jasper Wall

The angular power spectrum of the cosmic microwave background temperature anisotropy observed by WMAP has an anomalous dip at l~20 and bump at l~40. One explanation for this structure is the presence of features in the primordial curvature…

宇宙学与河外天体物理 · 物理学 2009-05-19 Michael J. Mortonson , Cora Dvorkin , Hiranya V. Peiris , Wayne Hu

Estimation of the angular power spectrum is one of the important steps in Cosmic Microwave Background (CMB) data analysis. Here, we present a nonparametric estimate of the temperature angular power spectrum for the Planck 2013 CMB data. The…

宇宙学与河外天体物理 · 物理学 2015-06-15 Amir Aghamousa , Arman Shafieloo , Mihir Arjunwadkar , Tarun Souradeep

CMB full-sky temperature data show a hemispherical asymmetry in power nearly aligned with the Ecliptic. In real space, this anomaly can be quantified by the temperature variance in the northern and southern Ecliptic hemispheres, with the…

宇宙学与河外天体物理 · 物理学 2020-10-14 Marcio O'Dwyer , Craig J. Copi , Johanna M. Nagy , C. Barth Netterfield , John Ruhl , Glenn D. Starkman

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…

宇宙学与河外天体物理 · 物理学 2015-05-18 M. Cruz , P. Vielva , E. Martínez-González , R. B. Barreiro

The temperature fluctuations of the Cosmic Microwave Background (CMB) are supposed to be distributed randomly in both magnitude and phase, following to the simplest model of inflation. In this paper, we look at the odd and even multipoles…

宇宙学与河外天体物理 · 物理学 2015-03-19 M. Hansen , A. M. Frejsel , J. Kim , P. Naselsky , F. Nesti

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

天体物理学 · 物理学 2009-11-11 Tarun Souradeep , Amir Hajian , Soumen Basak

We explore the low-l likelihood of the angular spectrum C(l) of masked CMB temperature maps using an adaptive importance sampler. We find that, in spite of a partial sky coverage, the likelihood distribution of each C(l) closely follows an…

宇宙学与河外天体物理 · 物理学 2015-05-13 K. Benabed , J. -F. Cardoso , S. Prunet , E. Hivon

In this paper, we explore the power of the cosmic microwave background (CMB) polarization (E-mode) data to corroborate four potential anomalies in CMB temperature data: the lack of large angular-scale correlations, the alignment of the…

In a concordant $\Lambda$ Cold Dark Matter ($\Lambda$CDM) model, large-angle Cosmic Microwave Background (CMB) temperature anisotropy due to linear perturbations in the local universe is not negligible. We explore a possible role of an…

宇宙学与河外天体物理 · 物理学 2012-04-09 Kaiki Taro Inoue

(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

We present a detailed analytical calculation of CMB temperature anisotropies \alpha_k and polarization \beta_k generated by scalar metric perturbations in synchronous gauge, parallel to our previous work with RGW as a generating source.…

宇宙学与河外天体物理 · 物理学 2015-06-04 Zheng Cai , Yang Zhang

Anisotropy of space-time is measured on the scale of the cosmic horizon, using the angular correlation function $C(\Theta)$ of cosmic microwave background (CMB) temperature at large angular separation $\Theta$. Even-parity correlation…

宇宙学与河外天体物理 · 物理学 2025-09-24 Craig Hogan , Ohkyung Kwon , Stephan S. Meyer , Nathaniel Selub , Frederick Wehlen

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 study the ellipticity of contour lines in the sky maps of the cosmic microwave background (CMB) as well as other measures of elongation. The sensitivity of the elongation on the resolution of the CMB maps which depends on the…

宇宙学与河外天体物理 · 物理学 2015-05-19 Ralf Aurich , Holger S. Janzer , Sven Lustig , Frank Steiner

Breakdown of rotational invariance of the primordial power spectrum manifests in the statistical anisotropy of the observed Cosmic Microwave Background (CMB) radiation. Hemispherical power asymmetry in the CMB may be caused due to a dipolar…

宇宙学与河外天体物理 · 物理学 2023-05-23 Md Ishaque Khan , Rajib Saha

We introduce a new mathematical tool (a direction-dependent probe) to analyse the randomness of purported isotropic Gaussian random fields on the sphere. We apply the probe to assess the full-sky cosmic microwave background (CMB)…

宇宙学与河外天体物理 · 物理学 2020-06-29 J. Hamann , Q. T. Le Gia , I. H. Sloan , Y. G. Wang , R. S. Womersley

We investigate a possible asymmetry in the statistical properties of the cosmic microwave background temperature field and to do so we construct an estimator aiming at detecting a dipolar modulation. Such a modulation is found to induce…

天体物理学 · 物理学 2009-11-10 Simon Prunet , Jean-Philippe Uzan , Francis Bernardeau , Tristan Brunier