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We examine the sky distribution of radio galaxies in the NRAO VLA Sky Survey (NVSS) and the Rapid ASKAP Continuum Survey (RACS). Analyses of these samples have reported tension between their inferred dipoles and the kinematic dipole of the…

宇宙学与河外天体物理 · 物理学 2024-06-05 Oliver T. Oayda , Vasudev Mittal , Geraint F. Lewis , Tara Murphy

We use linear estimators to determine the magnitude and direction of the cosmic radio dipole from the NRAO VLA Sky Survey (NVSS) and the Westerbork Northern Sky Survey (WENSS). We show that special attention has to be given to the issues of…

宇宙学与河外天体物理 · 物理学 2013-07-25 Matthias Rubart , Dominik J. Schwarz

The Cosmic Radio Dipole is of fundamental interest to cosmology. Recent studies revealed open questions about the nature of the observed Cosmic Radio Dipole. We use simulated source count maps to test a linear and a quadratic estimator for…

宇宙学与河外天体物理 · 物理学 2021-12-07 Thilo M. Siewert , Matthias Schmidt-Rubart , Dominik J. Schwarz

There have been recent reports of unexpectedly large velocity dipole in the NRAO VLA Sky Survey data. We investigate whether the excess in the NVSS dipole reported can be of cosmological origin. We assume a long wavelength inhomogeneous…

宇宙学与河外天体物理 · 物理学 2014-03-26 Shamik Ghosh

Our peculiar motion in a homogeneous and isotropic universe imprints a dipole in the cosmic microwave background (CMB) temperature field and similarly imprints a dipole in the distribution of extragalactic radio sources on the sky. Each of…

宇宙学与河外天体物理 · 物理学 2022-01-05 Calum Murray

We study the prospects to measure the cosmic radio dipole by means of continuum surveys with the Square Kilometre Array. Such a measurement will allow a critical test of the cosmological principle. It will test whether the cosmic rest frame…

宇宙学与河外天体物理 · 物理学 2018-10-16 Dominik J. Schwarz , Carlos A. P. Bengaly , Roy Maartens , Thilo M. Siewert

The source count dipole from wide-area radio continuum surveys allows us to test the cosmological standard model. Many radio sources have multiple components, which can cause an overdispersion of the source counts distribution. We account…

The dipole anisotropy seen in the {cosmic microwave background radiation} is interpreted as due to our peculiar motion. The Cosmological Principle implies that this cosmic dipole signal should also be present, with the same direction, in…

宇宙学与河外天体物理 · 物理学 2019-04-24 Carlos A. P. Bengaly , Thilo M. Siewert , Dominik J. Schwarz , Roy Maartens

We investigate dipole asymmetries in four large radio surveys, each spanning more than 80\% of the sky. Two of them, the Very Large Array Sky Survey (VLASS) and the Rapid ASKAP Continuum Survey (RACS), have recently yielded dipoles that…

宇宙学与河外天体物理 · 物理学 2024-10-10 Ashok K. Singal

The cosmic radio dipole is an anisotropy in the number counts of radio sources, analogous to the dipole seen in the cosmic microwave background (CMB). Measurements of source counts of large radio surveys have shown that though the radio…

宇宙学与河外天体物理 · 物理学 2023-07-05 J. D. Wagenveld , H-R. Klöckner , D. J. Schwarz

The dipole in the angular distribution of the cosmic microwave background (CMB) is attributed to the Doppler effect and our motion relative to the CMB rest frame. It is expected that observations of large-scale structures (LSSs) would also…

宇宙学与河外天体物理 · 物理学 2026-02-17 Arefeh Daei Rasouli , Haniyeh S. Tadayyoni , Shant Baghram , Sohrab Rahvar

We investigate the feasibility of measuring the effects of peculiar velocities in large-scale structure using the dipole of the redshift-space cross-correlation function. We combine number counts of galaxies with brightness-temperature…

宇宙学与河外天体物理 · 物理学 2018-01-01 Alex Hall , Camille Bonvin

We measure the angular two-point correlation and angular power spectrum from the NRAO VLA Sky Survey (NVSS) of radio galaxies. They are found to be consistent with the best-fit cosmological model from the Planck analysis, and with the…

宇宙学与河外天体物理 · 物理学 2016-06-29 Song Chen , Dominik J. Schwarz

Many observations in recent times have shown evidence against the standard assumption of isotropy in the Big Bang model. Introducing a superhorizon scalar metric perturbation has been able to explain some of these anomalies. In this work,…

宇宙学与河外天体物理 · 物理学 2021-07-21 Kaustav K. Das , Kishan Sankharva , Pankaj Jain

Large-scale structure surveys can be used to measure the dipole in the cosmic microwave background (CMB), in the luminosity distances inferred from type-Ia supernova observations, and in the spatial distribution of galaxies and quasars. The…

宇宙学与河外天体物理 · 物理学 2025-12-08 Jaiyul Yoo , Matteo Magi , Dragan Huterer

Observations of the large-scale structure (LSS) implicitly assume an ideal FLRW observer with the ambient structure having no influence on the observer. However, due to correlations in the LSS, cosmological observables are dependent on the…

宇宙学与河外天体物理 · 物理学 2019-08-05 Robert Reischke , Björn malte Schäfer , Krzysztof Bolejko , Geraint F. Lewis , Max Lautsch

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

We study the dipole anisotropy in number counts and flux density weighted number counts {or sky brightness} in the NRAO VLA Sky Survey (NVSS) data. The dipole anisotropy is expected due to our local motion with respect to the CMBR rest…

宇宙学与河外天体物理 · 物理学 2014-07-29 Prabhakar Tiwari , Rahul Kothari , Abhishek Naskar , Sharvari Nadkarni-Ghosh , Pankaj Jain

We are in motion against the cosmic backdrop. This motion is evidenced by the systematic temperature shift - or dipole anisotropy - observed in the Cosmic Microwave Background radiation (CMB). Because of the Doppler effect, the temperature…

天体物理学 · 物理学 2015-06-24 Chris Blake , Jasper Wall

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…

宇宙学与河外天体物理 · 物理学 2024-10-10 Ashok K. Singal
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