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We propose a data-driven approach to reconstruct the all-sky distribution of the dispersion measure contribution from the Galactic halo ($\mathrm{DM_{halo}}$) through a spherical harmonic expansion, enabling an investigation of its possible…

星系天体物理 · 物理学 2026-01-07 Yang Liu , Bao Wang , Puxun Wu , Jun-Jie Wei , Xue-Feng Wu

Measurements of the polarization angle and orientation of cosmological radio sources may be used to search for unusual effects in the propagation of light through the universe. Recently, Nodland and Ralston (astro-ph/9704196) have claimed…

天体物理学 · 物理学 2009-10-30 Sean M. Carroll , George B. Field

The polarization of the cosmic microwave background radiation will have a distribution of singularities and anti-singularities, points where the polarization vanishes for topological reasons. The statistics of polarization singularities…

天体物理学 · 物理学 2009-11-10 Dragan Huterer , Tanmay Vachaspati

Modern cosmology rests on the cosmological principle, that on large enough scales the Universe is both homogeneous and isotropic. A corollary is that galaxies' spin vectors should be isotropically distributed on the sky. This has been…

星系天体物理 · 物理学 2025-03-03 Dhruva Patel , Harry Desmond

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…

星系天体物理 · 物理学 2017-01-18 Behnam Javanmardi , Pavel Kroupa

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

We report a systematic rotation of the plane of polarization of electromagnetic radiation propagating over cosmological distances. The effect is extracted independently from Faraday rotation, and found to be correlated with the angular…

天体物理学 · 物理学 2008-11-26 Borge Nodland , John P. Ralston

We test whether or not the orbital poles of the systems in the solar neighbourhood are isotropically distributed on the celestial sphere. The problem is plagued by the ambiguity on the position of the ascending node. Of the 95 systems…

太阳与恒星天体物理 · 物理学 2014-11-19 J-L. Agati , D. Bonneau , A. Jorissen , E. Soulié , S. Udry , P. Verhas , J. Dommanget

We test the isotropy of the local distribution of galaxies using the 2MASS extended source catalogue. By decomposing the full sky survey into distinct patches and using a combination of photometric and spectroscopic redshift data, we use…

宇宙学与河外天体物理 · 物理学 2014-10-29 Stephen Appleby , Arman Shafieloo

An analysis of the position angles distribution of 10461 extended radio sources shows that the spatial orientation of the axes of these objects is anisotropic: they avoid the direction towards the Celestial Pole and are mostly oriented in…

宇宙学与河外天体物理 · 物理学 2014-11-20 V. R. Amirkhanyan

We analyse the distribution of position angles of 1 million galaxies from the Hyperleda catalogue, a sample that presents the galaxies coordinates in the celestial sphere, information that allows us to look for a possible privileged…

宇宙学与河外天体物理 · 物理学 2017-05-08 R. S. Menezes , C. Pigozzo , S. Carneiro

The distribution of the spin directions of galaxies has been a question in the past decade, with numerous Earth-based and space-based experiments showing that the distribution is not necessarily random. These experiments were based on…

宇宙学与河外天体物理 · 物理学 2024-04-23 Lior Shamir

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…

宇宙学与河外天体物理 · 物理学 2017-04-19 Biswajit Pandey

We present the first joint analysis of catalogs of radio galaxies and quasars to determine if their sky distribution is consistent with the standard $\Lambda$CDM model of cosmology. This model is based on the cosmological principle, which…

宇宙学与河外天体物理 · 物理学 2022-09-29 Nathan Secrest , Sebastian von Hausegger , Mohamed Rameez , Roya Mohayaee , Subir Sarkar

We present a novel method, based on a multiscale approach, for detecting anisotropy signatures in the arrival direction distribution of the highest energy cosmic rays. This method is catalog independent, i.e. it does not depend on the…

天体物理仪器与方法 · 物理学 2015-05-27 M. De Domenico , H. Lyberis

The peculiar motion of the Earth causes a dipole anisotropy modulation in the distant galaxy distribution due to the aberration effect. However, the amplitude and angular direction of the effect is not necessarily the same as those of the…

宇宙学与河外天体物理 · 物理学 2010-10-12 Yousuke Itoh , Kazuhiro Yahata , Masahiro Takada

We present a detailed statistical study of the observed anisotropy in radio polarizations from distant extragalactic objects. This anisotropy was earlier found by Birch (1982) and reconfirmed by Jain and Ralston (1999) in a larger data set.…

天体物理学 · 物理学 2009-11-10 Pankaj Jain , S. Sarala

We test the isotropy of radio polarization angle orientations with a robust and reliable dual frequency polarimetric survey of active galactic nuclei (AGN). We find that the polarization orientations are consistent with the assumption of…

宇宙学与河外天体物理 · 物理学 2019-02-06 Prabhakar Tiwari , Pankaj Jain

We analyze two volume limited galaxy samples from the SDSS photometric and spectroscopic data to test the isotropy in the local Universe. We use information entropy to quantify the global anisotropy in the galaxy distribution at different…

宇宙学与河外天体物理 · 物理学 2018-12-12 Suman Sarkar , Biswajit Pandey , Rishi Khatri

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
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