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We report measurements of the cosmic microwave background (CMB) power spectrum from the complete 2008 South Pole Telescope (SPT) data set. We analyze twice as much data as the first SPT power spectrum analysis, using an improved…

We present the first application of the weighted skew-spectra to analyze non-Gaussian information in galaxy survey data. Using the tree-level galaxy skew-spectra together with the one-loop power spectrum multipoles, we analyze the Sloan…

宇宙学与河外天体物理 · 物理学 2024-01-25 Shu-Fan Chen , Priyesh Chakraborty , Cora Dvorkin

Recent pulsar timing array (PTA) analyses show evidence for a gravitational wave background (GWB) with angular correlations consistent with the Hellings-Downs curve. Anisotropies are a key discriminator of the origin of this GWB, as they…

宇宙学与河外天体物理 · 物理学 2025-09-01 Valerie Domcke , Gabriele Franciolini , Mauro Pieroni

We report the detection of polarized anisotropy in the Cosmic Microwave Background radiation with the Degree Angular Scale Interferometer (DASI), located at the Amundsen-Scott South Pole research station. Observations in all four Stokes…

天体物理学 · 物理学 2011-05-05 J. Kovac , E. M. Leitch , C. Pryke , J. E. Carlstrom , N. W. Halverson , W. L. Holzapfel

In inflationary models with minimal amount of gravity waves, the primordial power spectrum of density fluctuations, $A_S^2(k)$, together with the basic cosmological parameters, completely specify the predictions for the cosmic microwave…

天体物理学 · 物理学 2009-10-31 Yun Wang , David N. Spergel , Michael A. Strauss

The detection of a dipole anisotropy in the sky distribution of sources in large-scale radio surveys can be used to constrain the magnitude and direction of our local motion with respect to an isotropically distributed extragalactic radio…

天体物理学 · 物理学 2009-11-13 Fronefield Crawford

Certain anomalies at large angular scales in the cosmic microwave background measured by WMAP have been suggested as possible evidence of breakdown of statistical isotropy(SI). Most CMB photons free-stream to the present from the surface of…

宇宙学与河外天体物理 · 物理学 2015-03-13 Moumita Aich , Tarun Souradeep

Pulsar timing arrays have found evidence for a low-frequency gravitational wave background (GWB). Assuming the GWB is produced by supermassive black hole binaries (SMBHBs), the next gravitational wave (GW) signals astronomers anticipate are…

高能天体物理现象 · 物理学 2024-04-24 Emiko C. Gardiner , Luke Zoltan Kelley , Anna-Malin Lemke , Andrea Mitridate

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

Statistical isotropy (SI) is one of the fundamental assumptions made in cosmological model building. This assumption is now being rigorously tested using the almost full sky measurements of the CMB anisotropies. A major hurdle in any such…

宇宙学与河外天体物理 · 物理学 2015-11-04 Pavan K. Aluri , Nidhi Pant , Aditya Rotti , Tarun Souradeep

We present a new method of constraining the mass and velocity anisotropy profiles of galaxy clusters from kinematic data. The method is based on a model of the phase space density which allows the anisotropy to vary with radius between two…

宇宙学与河外天体物理 · 物理学 2015-05-13 Radoslaw Wojtak , Ewa L. Lokas , Gary A. Mamon , Stefan Gottloeber

We investigate the angular anisotropy of the Hubble constant using the Cosmicflows-4 catalogue, with particular emphasis on three issues often treated only implicitly in the literature: the statistical formulation of the…

宇宙学与河外天体物理 · 物理学 2026-04-16 Vincenzo Salzano , J. Beltrán Jiménez , Dario Bettoni , Philippe Brax , Aurélien Valade

Statistical isotropy (SI) has been one of the simplifying assumptions in cosmological model building. Experiments like WMAP and PLANCK are attempting to test this assumption by searching for specific signals in the Cosmic Microwave…

宇宙学与河外天体物理 · 物理学 2011-11-21 Aditya Rotti , Moumita Aich , Tarun Souradeep

Recent high precision cosmological observations have revealed several anomalies in the Cosmic Microwave Background (CMB), indicating possible violations of statistical isotropy (nSI). Typically, nSI in the CMB sky is studied in the harmonic…

宇宙学与河外天体物理 · 物理学 2026-05-07 Vaishali R , Dipayan Mukherjee , Tarun Souradeep

The statistical expectation values of the temperature fluctuations of the Cosmic Microwave Background (CMB) are assumed to be preserved under rotations of the sky. We investigate the Statistical Isotropy (SI) of the CMB anisotropy maps…

天体物理学 · 物理学 2009-11-10 Amir Hajian , Tarun Souradeep , Neil Cornish

The cosmological principle is a cornerstone of the standard cosmological model. However, recent observations suggest potential deviations from this assumption, hinting at a small anisotropic expansion. Such an expansion can arise from…

The cosmological principle, as the cornerstone of the standard cosmological model, requires that the Universe be homogeneous and isotropic on large scales. As a fundamental assumption, it is constantly subjected to testing via various…

宇宙学与河外天体物理 · 物理学 2026-04-21 Jianping Hu , Chao Geng , Xuandong Jia , Zhaoyu Zuo , Taozhi Yang , Fayin Wang

Both the Wilkinson Microwave Anisotropy Probe (WMAP) and Planck observations reported the hemispherical asymmetry of the cosmic microwave background (CMB) temperature fluctuation. The hemispherical asymmetry might be stemmed from the…

宇宙学与河外天体物理 · 物理学 2014-05-13 Zhe Chang , Sai Wang

We report cosmic microwave background (CMB) power spectrum measurements from the first 100 sq. deg. field observed by the South Pole Telescope (SPT) at 150 and 220 GHz. On angular scales where the primary CMB anisotropy is dominant, ell ~<…

We investigate the weak lensing shear due to dark matter galaxy halos whose mass distributions, as projected on the sky, are nearly elliptical. The shear pattern due to these halos is anisotropic about the lens centers and we quantify the…

天体物理学 · 物理学 2007-05-23 T. G. Brainerd , C. O. Wright