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Related papers: Dipoles in the Sky

200 papers

We estimate the acceleration on the Local Group (LG) from the Two Micron All Sky Redshift Survey (2MRS). The sample used includes about 23,200 galaxies with extinction corrected magnitudes brighter than K_s=11.25 and it allows us to…

We present a general method for Bayesian inference of the underlying covariance structure of random fields on a sphere. We employ the Bipolar Spherical Harmonic (BipoSH) representation of general covariance structure on the sphere. We…

Cosmology and Nongalactic Astrophysics · Physics 2015-11-04 Santanu Das , Benjamin D. Wandelt , Tarun Souradeep

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…

Astrophysics · Physics 2009-12-30 Thomas J. Loredo , Eanna E. Flanagan , Ira M. Wasserman

Measurements of the cosmic microwave background (CMB) spectral $y$-distortion anisotropy offer a test for the statistical isotropy of the primordial density perturbations on $0.01\lesssim k{\rm Mpc}\lesssim 1$. We compute the 1-point…

Cosmology and Nongalactic Astrophysics · Physics 2019-01-28 Atsuhisa Ota

The cosmological principle states that our Universe is statistically homogeneous and isotropic at large scales. However, due to the relative motion of the Solar System, an additional kinematic dipole can be detected in the distribution of…

Cosmology and Nongalactic Astrophysics · Physics 2022-08-31 Yu-Tian Xu , Ji-Ping Dai , Dong Zhao , Jun-Qing Xia

The cosmic dipole anomaly, currently detected at a significance exceeding 5$\sigma$ in several independent survey poses a significant challenge to the standard model of cosmology. The Ellis & Baldwin formula provides a theoretical link…

Cosmology and Nongalactic Astrophysics · Physics 2026-04-29 Albert Bonnefous

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

Astrophysics · Physics 2007-05-23 Tarun Souradeep , Amir Hajian

In this paper we describe a Bayesian statistical method designed to infer the magnetic properties of stars observed using high-resolution circular spectropolarimetry in the context of large surveys. This approach is well suited for…

Solar and Stellar Astrophysics · Physics 2015-06-03 V. Petit , G. A. Wade

Upcoming large-scale structure surveys will be able to measure new features in the galaxy two point correlation function. Relativistic effects appear on large scales as subtle corrections to redshift-space distortions, showing up as a…

Cosmology and Nongalactic Astrophysics · Physics 2025-01-29 Daniel Sobral-Blanco , Camille Bonvin , Chris Clarkson , Roy Maartens

Using data from the SUGAR and the AGASA experiments taken during a 10 yr period with nearly uniform exposure to the entire sky, we search for large-scale anisotropy patterns in the arrival directions of cosmic rays with energies > 10^{19.6}…

The two point correlation function of the CMB temperature anisotropies is generally assumed to be statistically isotropic (SI). Deviations from this assumption could be traced to physical or observational artefacts and systematic effects.…

Cosmology and Nongalactic Astrophysics · Physics 2018-05-11 Saurabh Kumar , Aditya Rotti , Moumita Aich , Nidhi Pant , Sanjit Mitra , Tarun Souradeep

The cosmic dipole tension - the discrepancy between the Cosmic Microwave Background kinematic dipole and the matter dipole inferred from all-sky surveys poses a significant challenge to the Cosmological Principle, which dictates that the…

Cosmology and Nongalactic Astrophysics · Physics 2026-05-28 Vasudev Mittal , Geraint F. Lewis

If the diffuse extragalactic gamma ray emission traces the large scale structures of the universe, peculiar anisotropy patterns are expected in the gamma ray sky. In particular, because of the cutoff distance introduced by the absorption of…

Astrophysics · Physics 2014-10-13 A. Cuoco , S. Hannestad , T. Haugbølle , G. Miele , P. D. Serpico , H. Tu

The statistical cosmological principle states that observables on the celestial sphere are sampled from a rotationally invariant distribution. Previously certain large scale anomalies which violate this principle have been found, for…

Cosmology and Nongalactic Astrophysics · Physics 2018-11-01 Marvin Pinkwart , Dominik J. Schwarz

The excess of cosmic-ray positrons in the energy range from 10 GeV to few hundred GeV reported by PAMELA and AMS experiments is not consistent with a pure secondary origin and requires the introduction of a source term. The presence of…

Instrumentation and Methods for Astrophysics · Physics 2015-10-07 J. Berdugo , J. Casaus , C. Mana , M. A. Velasco

Much attention has been given to the problem of estimating cosmological parameters from the $C_l$ measured by future experiments. Many of the approaches which are being used either invoke poorly controlled approximations or are…

Astrophysics · Physics 2007-05-23 Benjamin D. Wandelt , Eric Hivon , Krzysztof M. Gorski

The observed distribution of galaxies has local transverse isotropy around the line-of- sight (LOS) with respect to the observer. The difference in the statistical clustering signal along and across the line-of-sight encodes important…

Cosmology and Nongalactic Astrophysics · Physics 2015-08-13 Lado Samushia , Enzo Branchini , Will Percival

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…

Cosmology and Nongalactic Astrophysics · Physics 2024-04-23 Lior Shamir

If gamma-ray bursts originate at cosmological distances then their angular distribution should exhibit a dipole in the direction of the solar motion relative to the cosmic microwave background. This is due to the combined effects of…

Astrophysics · Physics 2009-10-22 Eyal Maoz

The angular power spectrum is a powerful statistic for analysing cosmological signals imprinted in the clustering of matter. However, current galaxy and quasar surveys cover limited portions of the sky, and are contaminated by systematics…

Cosmology and Nongalactic Astrophysics · Physics 2013-10-29 Boris Leistedt , Hiranya V. Peiris , Daniel J. Mortlock , Aurélien Benoit-Lévy , Andrew Pontzen