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Related papers: The cosmological bulk flow in QCDM model: (In)cons…

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We study the late-time cosmological dynamics of a spatially flat FLRW universe in the framework of $f(Q)$ gravity, where $Q$ denotes the nonmetricity scalar. The matter sector is modeled as a bulk viscous fluid with a free equation-of-state…

General Relativity and Quantum Cosmology · Physics 2026-02-20 Simran Arora , Sai Swagat Mishra , P. K. Sahoo

We present results of cosmological N-body hydrodynamic chemistry simulations of primordial structure growth and evolution in a scenario with warm dark matter (WDM) having a mass of 3 keV (thermal relic) and compare with a model consisting…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-23 Umberto Maio , Matteo Viel

We explore observational constraints on a cosmological brane-world scenario in which the bulk is not empty. Rather, exchange of mass-energy between the bulk and the bane is allowed. The evolution of matter fields to an observer on the brane…

Astrophysics · Physics 2009-11-13 K. Umezu , K. Ichiki , T. Kajino , G. J. Mathews , R. Nakamura , M. Yahiro

The results from the Supernova Cosmology Project indicate a relation between cosmic distance and redshift that corresponds to an accelerating Universe, and, as a consequence, the presence of an energy component with negative pressure. This…

Astrophysics · Physics 2007-05-23 Daniel Enstrom , Sverker Fredriksson , Johan Hansson

The line-of-sight peculiar velocities are good indicators of the gravitational fluctuation of the density field. Techniques have been developed to extract cosmological information from the peculiar velocities in order to test the…

Cosmology and Nongalactic Astrophysics · Physics 2021-12-08 Fei Qin

Some remarkable examples of alternative cosmological theories are reviewed here, ranging from a compilation of variations on the Standard Model through the more distant quasi-steady-state cosmology, plasma cosmology, or universe models as a…

Cosmology and Nongalactic Astrophysics · Physics 2022-08-17 Martin Lopez-Corredoira , Louis Marmet

We present a comparison of void properties between the standard model of cosmology, $\Lambda$ Cold Dark Matter ($\Lambda$CDM), and two alternative cosmological models with evolving and interacting dark sectors: a quintessence model…

Cosmology and Nongalactic Astrophysics · Physics 2017-05-03 Eromanga Adermann , Pascal J. Elahi , Geraint F. Lewis , Chris Power

Measurements of cosmic flows enable us to test whether cosmological models can accurately describe the evolution of the density field in the nearby Universe. In this paper, we measure the low-order kinematic moments of the cosmic flow…

Cosmology and Nongalactic Astrophysics · Physics 2021-12-01 Fei Qin , David Parkinson , Cullan Howlett , Khaled Said

Using an approximate solution to the $N$-body problem in general relativity, and the \emph{principle of local isotropy at any point}, we construct a cosmological model, with zero curvature, for a universe composed uniquely by collision-less…

General Relativity and Quantum Cosmology · Physics 2014-09-11 Miguel Portilla

In this contribution we review the large body of work carried out over the past two decades to probe the dark matter in the local universe using redshift survey and peculiar velocity data. While redshift surveys have evolved rapidly over…

Astrophysics · Physics 2007-05-23 L. da Costa

Running vacuum models and viscous dark matter scenarios beyond perfect fluid idealization are two appealing theoretical strategies that have been separately studied as alternatives to solve some problems rooted in the $\Lambda$CDM…

General Relativity and Quantum Cosmology · Physics 2023-04-26 Norman Cruz , Gabriel Gomez , Esteban Gonzalez , Guillermo Palma , Angel Rincon

The recent robust and homogeneous analysis of the world's supernova distance-redshift data, together with cosmic microwave background and baryon acoustic oscillation data, provides a powerful tool for constraining cosmological models. Here…

The homogeneous, isotropic, and flat $\Lambda$CDM universe favored by observations of the cosmic microwave background can be described using only Euclidean geometry, locally correct Newtonian mechanics, and the basic postulates of special…

Cosmology and Nongalactic Astrophysics · Physics 2018-06-27 J. J. Condon , A. M. Matthews

The knowledge of the main features of the bulk flow in the Local Universe is important for a better determination of the relative motions there, an information that would contribute to a precise calculation of the Hubble-Lema\^{\i}tre law…

Cosmology and Nongalactic Astrophysics · Physics 2023-02-13 Felipe Avila , Jezebel Oliveira , Mariana L. S. Dias , Armando Bernui

In this paper we extend the range of consistency of a constant bulk viscosity model to redshifts up to $z\sim 8.1$. In this model the dark sector of the cosmic substratum is a viscous fluid with pressure $p= -\zeta \theta$, where $\theta$…

Cosmology and Nongalactic Astrophysics · Physics 2011-09-02 A. Montiel , N. Bretón

We propose a scenario in which the dark components of the Universe are manifestations of a single bulk viscous fluid. Using dynamical system methods, a qualitative study of the homogeneous, isotropic background scenario is performed in…

Astrophysics · Physics 2008-12-18 R. Colistete , J. C. Fabris , J. Tossa , W. Zimdahl

We study observational signatures of non-gravitational interactions between the dark components of the cosmic fluid, which can be either due to creation of dark particles from the expanding vacuum or an effect of the clustering of a…

Cosmology and Nongalactic Astrophysics · Physics 2019-12-10 Micol Benetti , Welber Miranda , Humberto A. Borges , Cassio Pigozzo , Saulo Carneiro , Jailson S. Alcaniz

We investigate the late-time cosmic acceleration within the framework of viscous $f(T,L_m)$ gravity, where the gravitational action depends on both the torsion scalar $T$ and the matter Lagrangian $L_m$. In this context, the Universe is…

General Physics · Physics 2026-03-24 M. Koussour , Alnadhief H. A. Alfedeel , S. Muminov , J. Rayimbaev

A hierarchical Bayesian model is applied to the Cosmicflows-3 catalog of galaxy distances in order to derive the peculiar velocity field and distribution of matter within $z \sim 0.054$. The model assumes the $\Lambda$CDM model within the…

Cosmology and Nongalactic Astrophysics · Physics 2019-01-23 R. Graziani , H. M. Courtois , G. Lavaux , Y. Hoffman , R. B. Tully , Y. Copin , D. Pomarède

We present a cosmographic study designed to test the simplest type of accelerating cosmology: a flat universe with matter and a cosmological constant ($\Lambda$). Hubble series expansions are fit to the SCP Union2.1 supernova data set to…

Cosmology and Nongalactic Astrophysics · Physics 2015-11-17 Brett Bochner , Damon Pappas , Menglu Dong