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We solve analytically and numerically the generalized Einstein equations in scalar-tensor cosmologies to obtain the evolution of dark energy and matter linear perturbations. We compare our results with the corresponding results for…

Cosmology and Nongalactic Astrophysics · Physics 2010-05-25 J. C. Bueno Sanchez , L. Perivolaropoulos

In a previous paper, we proposed a heterotic dark energy model, called $\Lambda$HDE, in which dark energy is composed of two components: cosmological constant (CC) and holographic dark energy (HDE). The aim of this work is to give a more…

Cosmology and Nongalactic Astrophysics · Physics 2017-02-17 Shuang Wang , Sixiang Wen , Lanjun Zhou , Miao Li

We have searched for and estimated the possible gravitational influence of dark matter in the Solar system based on the EPM2011 planetary ephemerides using about 677 thousand positional observations of planets and spacecraft. Most of the…

Earth and Planetary Astrophysics · Physics 2013-06-25 N. P. Pitjev , E. V. Pitjeva

A recently proposed Dynamical Space-time Cosmology (DSC) that unifies dark energy and dark matter is studied. The general action of this scenario includes a Lagrange multiplier, which is coupled to the energy momentum tensor and a scalar…

General Relativity and Quantum Cosmology · Physics 2019-06-10 Fotios K. Anagnostopoulos , David Benisty , Spyros Basilakos , Eduardo I. Guendelman

We investigate various dark energy models by taking into account the thermal effects induced from Hawking radiation on the apparent horizon of the Universe, for example near a finite-time future singularity. If the dark energy density…

General Relativity and Quantum Cosmology · Physics 2021-02-17 Artyom V. Astashenok , Sergei D. Odintsov , Vasilis K. Oikonomou

Asymmetric dark matter models are based on the hypothesis that the present-day abundance of dark matter has the same origin as the abundance of ordinary or visible matter: an asymmetry in the number densities of particles and antiparticles.…

High Energy Physics - Phenomenology · Physics 2013-08-02 Kalliopi Petraki , Raymond R. Volkas

A new phenomenological dark energy model, originally associated to the large-scale structure formation and considered as a solution to the fine-tuning and coincidence problems related to the cosmological constant, was analyzed within the…

General Relativity and Quantum Cosmology · Physics 2026-03-05 A. Kazım Çamlıbel

The abundance of the most massive objects in the Universe at different epochs is a very sensitive probe of the cosmic background evolution and of the growth history of density perturbations, and could provide a powerful tool to distinguish…

Cosmology and Nongalactic Astrophysics · Physics 2012-02-22 Marco Baldi

We study the evolution of galaxy clustering in various cosmological models with quintessence. We investigate how the analytical predictions vary with change of dark energy equation of state $w_X$. Comparing these predictions against…

Astrophysics · Physics 2015-06-24 Dipak Munshi , Cristiano Porciani , Yun Wang

The exact nature of dark energy is currently unknown and its cosmological perturbations, when dark energy is assumed not to be the cosmological constant, are usually modeled as adiabatic. Here we explore the possibility that dark energy…

Cosmology and Nongalactic Astrophysics · Physics 2020-11-23 Rubén Arjona , Juan García-Bellido , Savvas Nesseris

In the early Universe, dark energy may have a non-negligible contribution. If this dark energy corresponds to an early cosmological constant, it leads to a late-time huge dark energy density which is much larger than what is expected for…

General Relativity and Quantum Cosmology · Physics 2023-01-26 H. Mohseni Sadjadi , V. Anari

We examine the dark energy and matter densities allowed by precision measurements of distances out to various redshifts, in the presence of spatial curvature and (near) arbitrary behavior of the dark energy equation of state. Degeneracies…

Cosmology and Nongalactic Astrophysics · Physics 2011-09-22 Arman Shafieloo , Eric V. Linder

The evolution of matter density perturbations in two-component model of the Universe consisting of dark energy (DE) and dust-like matter (M) is considered. We have analyzed it for two kinds of DE with $\omega\ne -1$: a) unperturbed energy…

Astrophysics · Physics 2007-05-23 Yu. Kulinich , B. Novosyadlyj

This short review was prepared as an introduction to the Royal Society's 'Dark Matter' conference. It addresses the embarrassing fact that 95% of the universe is unaccounted for. Favoured dark matter candidates are axions or…

Astrophysics · Physics 2010-12-09 Martin J. Rees

Within the standard cosmological scenario the Universe is found to be filled by obscure components (dark matter and dark energy) for ~95% of its energy budget. In particular, almost all the matter content in the Universe is given by dark…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-04 Crescenzo Tortora , Philippe Jetzer , Nicola R. Napolitano

We study the imprint of Dark Energy on the density profile of Dark Matter halos using a set of high-resolution large volume cosmological N-body simulations from the Dark Energy Universe Simulation Series (DEUSS). We first focus on the…

Cosmology and Nongalactic Astrophysics · Physics 2014-01-03 Irène Balmès , Yann Rasera , Pier-Stefano Corasaniti , Jean-Michel Alimi

Dark energy (DE) plays an important role in the expansion history of our universe. But we only got limited knowledge about its nature and properties after decades of study.In most numerical researches, DE is usually considered as a…

Cosmology and Nongalactic Astrophysics · Physics 2021-08-02 Ke Wang , Lu Chen

Entropic cosmology with the R\'{e}nyi entropy of the apparent horizon $S_R=(1/\alpha)\ln(1+\alpha S_{BH})$, where $S_{BH}$ is the Bekenstein--Hawking entropy, is studied. By virtue of the thermodynamics-gravity correspondence a model of…

General Physics · Physics 2026-05-04 S. I. Kruglov

We derive and analyze a class of spherically symmetric cosmological models whose source is an interactive mixture of inhomogeneous cold dark matter (DM) and a generic homogeneous dark energy (DE) fluid. If the DE fluid corresponds to a…

Astrophysics · Physics 2009-11-10 Roberto A Sussman , Israel Quiros , Osmel Martin Gonzalez

Cosmological observations strongly suggest the presence of dark energy which comprises the majority of the current energy density of the universe. The equation of state relating the pressure and energy density of this dark energy, p = w…

Astrophysics · Physics 2007-05-23 Eric Gawiser