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We consider an anisotropic inhomogeneous model to simulate measured vertical-seismic-profile traveltimes. In this model, we assume that velocity increases linearly with depth and anisotropy is the result of elliptical velocity dependence.…

Geophysics · Physics 2020-12-08 Ayiaz Kaderali , Theodore Stanoev

Peculiar velocities encode rich cosmological information, but their transverse components are hard to measure. Here, we present the first observations of a novel effect of transverse velocities: the dipole signatures that they imprint on…

Cosmology and Nongalactic Astrophysics · Physics 2025-06-16 Yan-Chuan Cai , John A. Peacock , Anna de Graaff , Shadab Alam

This is a somewhat extended version of the original July 93 report. It is proved that the cosmological density perturbation is associated with a peculiar velocity field. This allows a simple formulation of cosmological perturbation theory,…

Astrophysics · Physics 2010-11-01 Marco Bruni , David H. Lyth

We present a realistic modeling of the dipole component of the projected sky distribution of NVSS radio galaxies. The modeling relies on mock catalogs generated within the context of $\Lambda$CDM cosmology, in the linear regime of structure…

Cosmology and Nongalactic Astrophysics · Physics 2016-04-07 Prabhakar Tiwari , Adi Nusser

It has been recognized that the observables of large-scale structure (LSS) is susceptible to long-wavelength density and tidal fluctuations whose wavelengths exceed the accessible scale of a finite-volume observation, referred to as the…

Cosmology and Nongalactic Astrophysics · Physics 2021-12-02 Atsushi Taruya , Kazuyuki Akitsu

Observations reveal a `bulk flow' in the local Universe which is faster and extends to much larger scales than is expected around a typical observer in the standard $\Lambda$CDM cosmology. This is expected to result in a scale-dependent…

Cosmology and Nongalactic Astrophysics · Physics 2019-11-27 Jacques Colin , Roya Mohayaee , Mohamed Rameez , Subir Sarkar

We examine all-sky cosmic microwave background (CMB) temperature maps on large angular scales to compare their consistency with two scenarios: the standard inflationary quantum picture, and a distribution constrained to have a universal…

Cosmology and Nongalactic Astrophysics · Physics 2022-04-13 Nathaniel Selub , Frederick Wehlen , Craig Hogan , Stephan S. Meyer

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…

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

A wide range of large scale observations hint towards possible modifications on the standard cosmological model which is based on a homogeneous and isotropic universe with a small cosmological constant and matter. These observations, also…

Cosmology and Nongalactic Astrophysics · Physics 2014-01-21 Leandros Perivolaropoulos

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…

Cosmology and Nongalactic Astrophysics · Physics 2021-12-07 Thilo M. Siewert , Matthias Schmidt-Rubart , Dominik J. Schwarz

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

Recent analyses of large-scale structure and redshift surveys have reported significant dipolar anisotropies in the local Universe that are not straightforwardly attributable to a global kinematic boost. When interpreted within standard…

Cosmology and Nongalactic Astrophysics · Physics 2026-05-05 Erick Pastén

We present a map of the Cosmic Microwave Background (CMB) anisotropies induced by the late Integrated Sachs Wolfe effect. The map is constructed by combining the information of the WMAP 7-yr CMB data and the NRAO VLA Sky Survey (NVSS)…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-11 R. B. Barreiro , P. Vielva , A. Marcos-Caballero , E. Martinez-Gonzalez

Recent measurements using catalogues of quasars and radio galaxies have shown that the dipole anisotropy in the large-scale distribution of matter is about twice as large as is expected in the standard $\Lambda$CDM model, indeed in any…

Cosmology and Nongalactic Astrophysics · Physics 2024-10-15 Sebastian von Hausegger

We propose a novel representation of cosmic microwave anisotropy maps, where each multipole order l is represented by l unit vectors pointing in directions on the sky and an overall magnitude. These "multipole vectors and scalars" transform…

Astrophysics · Physics 2008-11-26 C. J. Copi , D. Huterer , G. D. Starkman

The observational behavior of spherically symmetric inhomogeneous cosmological models is studied, which consist of inner and outer homogeneous regions connected by a shell or an intermediate self-similar region. It is assumed that the…

Astrophysics · Physics 2009-10-31 Kenji Tomita

In this manuscript, we investigate the patterns satisfied by the cosmological anisotropy under the hypothesis of the observers being co-moving with a perfect fluid whose induced space sections are homogeneous with vanishing scalar…

General Relativity and Quantum Cosmology · Physics 2021-03-31 Leandro G. Gomes

In the standard (LCDM) model of cosmology the universe has emerged out of an early homogeneous and isotropic phase. Structure formation is associated with the growth of density irregularities and peculiar velocities. Our Local Group is…

Cosmology and Nongalactic Astrophysics · Physics 2017-02-09 Yehuda Hoffman , Daniel Pomarede , R. Brent Tully , Helene Courtois

We confirm for the first time the existence of distinctive halo bias associated with the quadrupolar type of statistical anisotropy (SA) of the linear matter density field using cosmological $N$-body simulations. We find that the…

Cosmology and Nongalactic Astrophysics · Physics 2025-05-19 Shogo Masaki , Maresuke Shiraishi , Takahiro Nishimichi , Teppei Okumura , Shuichiro Yokoyama

Measurements of the SNe Ia Hubble diagram which suggest that the universe is accelerating due to the effect of dark energy may be biased because we are located in a 200-300 Mpc underdense "void" which is expanding 20-30% faster than the…

Astrophysics · Physics 2011-02-09 Paul Hunt , Subir Sarkar