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Recent released Planck data and other astronomical observations show that the universe may be anisotropic on large scales. Inspired by this, anisotropic cosmological models have been proposed. We note that the Finsler-Randers spacetime…

Cosmology and Nongalactic Astrophysics · Physics 2014-03-25 Zhe Chang , Xin Li , Hai-Nan Lin , Sai Wang

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…

Cosmology and Nongalactic Astrophysics · Physics 2019-08-20 Shabbir Shaikh , Suvodip Mukherjee , Santanu Das , Benjamin D. Wandelt , Tarun Souradeep

Following earlier authors, we re-examine constraints on the radial velocity anisotropy of generic stellar systems using arguments for phase space density positivity, stability, and separability. It is known that although the majority of…

Astrophysics of Galaxies · Physics 2015-06-19 Jeremy A. Barber , Hongsheng Zhao

We apply our symmetry based Power tensor technique to test conformity of PLANCK Polarization maps with statistical isotropy. On a wide range of angular scales (l=40-150), our preliminary analysis detects many statistically anisotropic…

Cosmology and Nongalactic Astrophysics · Physics 2020-02-27 Pranati K. Rath , Pramoda Kr. Samal , Srikanta Panda , Debesh D. Mishra , Pavan K. Aluri

We report a possible dipole anisotropy on acceleration scale $g_{\dag}$ with 147 rotationally supported galaxies in local Universe. It is found that a monopole and dipole correction for the radial acceleration relation can better describe…

Cosmology and Nongalactic Astrophysics · Physics 2018-10-16 Zhe Chang , Hai-Nan Lin , Zhi-Chao Zhao , Yong Zhou

There have recently been several claims of an asymmetric distribution of large scale fluctuations in the WMAP data. I review some recent results from a test of isotropy of the power spectrum at all scales and show how the power is…

Astrophysics · Physics 2007-05-23 F. K. Hansen

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…

Astrophysics · Physics 2011-02-11 Nicolaas E. Groeneboom , Hans Kristian Eriksen

Motivated by the large-scale asymmetry observed in the cosmic microwave background sky, we consider a specific class of anisotropic cosmological models -- Bianchi type VII_h -- and compare them to the WMAP first-year data on large angular…

Astrophysics · Physics 2009-11-10 T. R. Jaffe , A. J. Banday , H. K. Eriksen , K. M. Gorski , F. K. Hansen

Anomalies in the large-scale CMB temperature sky measured by WMAP have been suggested as possible evidence for a violation of statistical isotropy on large scales. In any physical model for broken isotropy, there are testable consequences…

Astrophysics · Physics 2008-12-18 Cora Dvorkin , Hiranya V. Peiris , Wayne Hu

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…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-28 P. Naselsky , M. Hansen , J. Kim

The distribution of arrival directions of ultra-high energy cosmic rays may yield clues to their mysterious origin. We introduce a method of {\it invariant statistics} to analyze cosmic ray data which eliminates coordinate-dependent…

Astrophysics · Physics 2009-11-07 Soebur Razzaque , John P. Ralston

The measurement of the anisotropy in the arrival direction of cosmic rays is complementary to the study of their energy spectrum and chemical composition to understand their origin and propagation. It is also a tool to probe the structure…

High Energy Astrophysical Phenomena · Physics 2014-07-09 G. Di Sciascio , R. Iuppa

We present results of elaborate four-dimensional simulations of the propagation of ultra-high-energy cosmic rays (UHECR), which are based on a realistic astrophysical scenario. The distribution of the arrival directions of the UHECR is…

High Energy Astrophysical Phenomena · Physics 2018-02-19 David Wittkowski , Karl-Heinz Kampert

This paper proposes and discusses a test of the chemical composition of ultra-high energy cosmic rays that relies on the anisotropy patterns measured as a function of energy. In particular, we show that if one records an anisotropy signal…

High Energy Astrophysical Phenomena · Physics 2009-11-13 Martin Lemoine , Eli Waxman

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…

Cosmology and Nongalactic Astrophysics · Physics 2021-05-12 Pablo Fosalba , Enrique Gaztanaga

Several cosmic-ray observatories have provided a high accuracy map of the sky at TeV--PeV energies. The data reveals an O(0.1%) deficit from north galactic directions that peaks at 10 TeV and then evolves with the energy, together with…

High Energy Astrophysical Phenomena · Physics 2015-06-22 Eduardo Battaner , Joaquin Castellano , Manuel Masip

We prepare the full sky radio galaxy map ($|b|>10^{\circ}$) using the north NVSS and south SUMSS galaxy catalogs and study the large scale multipoles anomalies. These galaxies are roughly at redshift $z \sim 0.8$ and therefore tracing the…

Cosmology and Nongalactic Astrophysics · Physics 2019-07-01 Prabhakar Tiwari , Pavan K. Aluri

Recently, an anisotropic cosmological model was proposed. An arbitrary 1-form, which picks out a privileged axis in the universe, was added to the Friedmann-Robertson-Walker line element. The distance-redshift relation was modified such…

Cosmology and Nongalactic Astrophysics · Physics 2014-05-14 Zhe Chang , Xin Li , Hai-Nan Lin , Sai Wang

We test anisotropic dark energy models with the 7-year WMAP temperature observations data. In the presence of imperfect sources, due to large-scale gradients or anisotropies in the dark energy field, the CMB sky will be distorted…

Cosmology and Nongalactic Astrophysics · Physics 2014-05-08 Magnus J. Axelsson , Frode K. Hansen , Tomi Koivisto , David F. Mota

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
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