English
Related papers

Related papers: Large-Scale Coherent Dipole Anisotropy ?

200 papers

Measurements of commensurability oscillations in GaAs/AlGaAs two-dimensional (2D) hole systems grown on GaAs (311)A substrates reveal a remarkable anisotropy: the amplitude of the measured commensurability oscillations along the…

Mesoscale and Nanoscale Physics · Physics 2009-10-31 Jeng-Bang Yau , Jeng-Ping Lu , Harindran C. Manoharan , Mansour Shayegan

We study several anisotropic inflationary models and their implications for the observed violation of statistical isotropy in the CMBR data. In two of these models the anisotropy decays very quickly during the inflationary phase of…

Cosmology and Nongalactic Astrophysics · Physics 2017-09-15 Pranati K. Rath , Tanmay Mudholkar , Pankaj Jain , Pavan K. Aluri , Sukanta Panda

We aim to settle the debate regarding the fraction of the Local Group's peculiar velocity that is induced by structures beyond the Great Attractor by calculating the dipole anisotropy of the largest, all-sky, truly X-ray selected cluster…

Astrophysics · Physics 2009-11-13 Dale D. Kocevski , Harald Ebeling

The existence of the cosmic ray Halo in our Galaxy has been discussed for more than half a century. If it is real it could help to explain some puzzling features of the cosmic ray flux: its small radial gradient, nearly perfect isotropy and…

Astrophysics of Galaxies · Physics 2015-06-19 Anatoly Erlykin , Arnold Wolfendale

We use information entropy to test the isotropy in the nearby galaxy distribution mapped by the Two Micron All-Sky redshift survey (2MRS). We find that the galaxy distribution is highly anisotropic on small scales. The radial anisotropy…

Cosmology and Nongalactic Astrophysics · Physics 2017-04-19 Biswajit Pandey

The unprecedented sky coverage and photometric uniformity of the Two Micron All Sky Survey (2MASS) provides a rich resource for investigating the galaxies populating the local Universe. A full characterization of the large-scale clustering…

Astrophysics · Physics 2009-11-07 Ariyeh H. Maller , Daniel H. McIntosh , Neal Katz , Martin D. Weinberg

We present the first study of the isotropy of the distribution of morphological types of galaxies in the Local Universe out to around 200 Mpc using more than 60,000 galaxies from the HyperLeda database. We divide the sky into two opposite…

Astrophysics of Galaxies · Physics 2017-01-18 Behnam Javanmardi , Pavel Kroupa

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…

Cosmology and Nongalactic Astrophysics · Physics 2026-04-21 Jianping Hu , Chao Geng , Xuandong Jia , Zhaoyu Zuo , Taozhi Yang , Fayin Wang

The hypothesis that the late Universe is isotropic and homogeneous is adopted by most cosmological studies. The expansion rate $H_0$ is thought to be spatially constant, while bulk flows are often presumed to be negligible compared to the…

Cosmology and Nongalactic Astrophysics · Physics 2021-06-02 K. Migkas , F. Pacaud , G. Schellenberger , J. Erler , N. T. Nguyen-Dang , T. H. Reiprich , M. E. Ramos-Ceja , L. Lovisari

We characterize the radial and angular variance of the Hubble flow in the COMPOSITE sample of 4534 galaxies, on scales in which much of the flow is in the nonlinear regime. With no cosmological assumptions other than the existence of a…

Cosmology and Nongalactic Astrophysics · Physics 2013-10-30 David L. Wiltshire , Peter R. Smale , Teppo Mattsson , Richard Watkins

We use the PSCz IRAS galaxy redshift survey to analyze the cosmological galaxy dipole out to a distance 300 h$^{-1}$ Mpc. The masked area is filled in three different ways, firstly by sampling the whole sky at random, secondly by using…

A large peculiar velocity of the intergalactic medium produces a Doppler shift of the cosmic microwave background with a frequency-dependent quadrupole term. This quadrupole will act as a source for polarization of the cosmic microwave…

Cosmology and Nongalactic Astrophysics · Physics 2014-02-20 Elinore Roebber , Gilbert Holder

We have used the two IRAS redshift surveys, 1.2-Jy (Fisher et al 1995) and PSCz (Saunders et al 2000), to model the linear velocity fields within a redshift of 8,000 km/s and have compared them in redshift space. The two velocity fields…

Astrophysics · Physics 2007-05-23 Luis Teodoro , Enzo Branchini , Carlos Frenk

Sky distributions of large samples of distant active galactic nuclei (AGNs) have shown dipoles significantly larger than the cosmic microwave background (CMB) dipole. However, a recent Bayesian analysis of the QUAIA sample, comprising 1.3…

Cosmology and Nongalactic Astrophysics · Physics 2024-10-10 Ashok K. Singal

Comparing the gravitational acceleration induced on the Local Group of galaxies by different tracers of the underline density field we estimate, within the linear gravitational instability theory and the linear biasing ansatz, their…

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…

Astrophysics · Physics 2009-11-13 Fronefield Crawford

Large-scale modes in the temperature anisotropy power spectrum C_l measured by the Wilkinson Microwave Anisotropy Probe (WMAP), seem to have lower amplitudes (C_2, C_3 and C_4) than that expected in the so called concordance LCDM model. In…

Astrophysics · Physics 2009-11-07 E. Gaztanaga , J. Wagg , T. Multamaki , A. Montana , D. H. Hughes

We test the usual hypothesis that the Cosmic Microwave Background (CMB) dipole, its largest anisotropy, is due to our peculiar velocity with respect to the Hubble flow by measuring independently the Doppler and aberration effects on the CMB…

Cosmology and Nongalactic Astrophysics · Physics 2021-09-06 Pedro da Silveira Ferreira , Miguel Quartin

The largest anisotropy in the cosmic microwave background (CMB) is the $\approx 3$ mK dipole assumed to be due to our velocity with respect to the CMB. Using the four year data set from all six channels of the COBE Differential Microwave…

Astrophysics · Physics 2016-08-30 C. H. Lineweaver , L. Tenorio , G. F. Smoot , P. Keegstra , A. J. Banday , P. Lubin

We study numerically the anisotropy of the cosmic ray (CR) flux emitted by a single source calculating the trajectories of individual CRs. We show that the contribution of a single source to the observed anisotropy is instead determined…

High Energy Astrophysical Phenomena · Physics 2015-08-26 V. Savchenko , M. Kachelriess , D. V. Semikoz