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Shortly the vacuum component of the Universe from the geometry point of view and from the point of view of the standard model of physics of elementary particles is discussed. Some arguments are given to the calculated value of the…

Astrophysics · Physics 2009-12-15 V. Burdyuzha , G. Vereshkov

The discrepancies between recently reported experimental values of the gravitational constant were analysed within an inertia interpretation of MOND theory. According to this scenario the relative gravitational acceleration between a test…

General Relativity and Quantum Cosmology · Physics 2016-10-31 Norbert Klein

The cosmological dynamics of gravitational clustering satisfies an approximate invariance with respect to the cosmological parameters that is often used to simplify analytical computations. We describe how this approximate symmetry gives…

Cosmology and Nongalactic Astrophysics · Physics 2014-07-02 Patrick Valageas

The paper aims to introduce a new symmetry principle in the space-time geometry through the elimination of the classical idea of rest and by including a universal minimum limit of speed in the subatomic world. Such a limit, unattainable by…

General Relativity and Quantum Cosmology · Physics 2016-11-08 Claudio Nassif

We discuss some mathematical aspects of the problem of inverting gravitational field data to extract the underlying mass distribution. While the forward problem of computing the gravity field from a given mass distribution is mathematically…

Mathematical Physics · Physics 2015-03-17 Ulvi Yurtsever , Caren Marzban , Marina Meila

We show that in a hierarchical clustering model the low-order statistics of the density and the peculiar velocity fields can all be modelled semianalytically for a given cosmology and an initial density perturbation power spectrum $P(k)$.…

Astrophysics · Physics 2015-06-24 H. J. Mo , Y. P. Jing , G. Börner

We consider a two-dimensional Coulomb gas of positive and negative pointlike unit charges interacting via a logarithmic potential. The density (rather than the charge) correlation functions are studied. In the bulk, the form-factor theory…

Statistical Mechanics · Physics 2007-05-23 L. Šamaj , B. Jancovici

We present high--spatial resolution studies of the density field as predicted by Lagrangian perturbation approximations up to the third order. The first--order approximation is equivalent to the ``Zel'dovich approximation'' for the type of…

Astrophysics · Physics 2011-05-23 Thomas Buchert , Georgios Karakatsanis , Robert Klaffl , Peter Schiller

General relativistic entropic acceleration theory may explain the present cosmic acceleration from first principles without the need of introducing a cosmological constant. Following the covariant formulation of non-equilibrium phenomena in…

General Relativity and Quantum Cosmology · Physics 2021-10-20 Juan Garcia-Bellido , Llorenc Espinosa-Portales

We study the peculiar motion of non-relativistic matter in a fully covariant way. The exact nonlinear equations are derived and then applied to the case of pressure-free matter, moving relatively to a quasi-Newtonian Eulerian frame. Our…

Astrophysics · Physics 2009-11-07 George F. R. Ellis , Christos G. Tsagas

We consider an effective viscous pressure as the result of a backreaction of inhomogeneities within Buchert's formalism. The use of an effective metric with a time-dependent curvature radius allows us to calculate the luminosity distance of…

General Relativity and Quantum Cosmology · Physics 2016-04-13 Rodrigo M. Barbosa , G. Eddy , I. Chirinos , Winfried Zimdahl , Oliver F. Piattella

We study the possibility of using correlations between spatial modulations in the observed luminosity distribution of galaxies and the underlying density field as a cosmological probe. Considering redshift ranges, where magnification…

Cosmology and Nongalactic Astrophysics · Physics 2018-08-07 Martin Feix

It is shown that a first-order relativistic perturbation theory for the open, flat or closed Friedmann-Lemaitre-Robertson-Walker universe admits one, and only one, gauge-invariant quantity which describes the perturbation to the energy…

General Relativity and Quantum Cosmology · Physics 2014-03-25 P. G. Miedema

The recent findings of Romanowsky et al., of an ``unexpectedly'' small mass discrepancy within 5 effective radii in several elliptical galaxies, are not surprising in the context of MOND. As we show here, they are, in fact, in full…

Astrophysics · Physics 2009-11-10 Mordehai Milgrom , Robert H. Sanders

Peculiar velocities are the motions of galaxies due to the gravitational influence of large-scale structure, and thus are an important cosmological probe of the underlying matter density field. In recent years the number of surveys designed…

Cosmology and Nongalactic Astrophysics · Physics 2025-02-19 Ryan J. Turner

The concentration-mass relations proposed by Prada et al. (2012) and by Duffy et al. (2008) on the scales of galaxy clusters show some of the largest discrepancies among all the works present in literature. This is surprising because they…

Cosmology and Nongalactic Astrophysics · Physics 2013-03-26 M. Meneghetti , E. Rasia

The line-of-sight peculiar velocities of galaxies contribute to their observed redshifts, breaking the translational invariance of galaxy clustering down to a rotational invariance around the observer. This becomes important when the…

Cosmology and Nongalactic Astrophysics · Physics 2020-07-29 Emanuele Castorina , Martin White

Applications in data science, shape analysis and object classification frequently require comparison of probability distributions defined on different ambient spaces. To accomplish this, one requires a notion of distance on a given class of…

Metric Geometry · Mathematics 2022-07-19 Facundo Mémoli , Tom Needham

Fractional cosmology modifies the standard derivative to Caputo's fractional derivative of order $\mu$, generating changes in General Relativity. Friedmann equations are modified, and the evolution of the species densities depends on $\mu$…

General Relativity and Quantum Cosmology · Physics 2022-10-26 Miguel A. García-Aspeitia , Guillermo Fernandez-Anaya , A. Hernández-Almada , Genly Leon , Juan Magaña

We find the probability density function $\mathcal{P}(V_{\texttt{r}})$ of the relativistic relative velocity for two colliding particles in a non-degenerate relativistic gas. The distribution reduces to Maxwell distribution for the relative…

Cosmology and Nongalactic Astrophysics · Physics 2014-06-02 M. Cannoni
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