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A new kind of accelerating flat model with no dark energy that is fully dominated by cold dark matter (CDM) is investigated. The number of CDM particles is not conserved and the present accelerating stage is a consequence of the negative…

Astrophysics · Physics 2014-11-18 J. A. S. Lima , F. E. Silva , R. C. Santos

A new accelerating cosmology driven only by baryons plus cold dark matter (CDM) is proposed in the framework of general relativity. In this model the present accelerating stage of the Universe is powered by the negative pressure describing…

Cosmology and Nongalactic Astrophysics · Physics 2010-12-06 J. A. S. Lima , J. F. Jesus , F. A. Oliveira

Cold + Hot Dark Matter (CHDM) is perhaps the best theory of cosmic structure formation {\it if} the cosmological matter density is near critical (i.e., $\Omega_0 \approx 1$) and {\it if} the expansion rate is not too large (i.e. $h \equiv…

High Energy Physics - Phenomenology · Physics 2007-05-23 Joel Primack

We investigate the creation of cold dark matter (CCDM) cosmology as an alternative to explain the cosmic acceleration. Particular attention is given to the evolution of density perturbations and constraints coming from recent observations.…

Cosmology and Nongalactic Astrophysics · Physics 2014-04-11 Rudnei O. Ramos , Marcelo Vargas dos Santos , Ioav Waga

The standard procedure to explain the accelerated expansion of the Universe is to assume the existence of an exotic component with negative pressure, generically called dark energy. Here, we propose a new accelerating flat cosmology without…

Cosmology and Nongalactic Astrophysics · Physics 2025-02-21 P. W. R. Lima , J. A. S. Lima , J. F. Jesus

We propose an alternative, nonsingular, cosmic scenario based on gravitationally induced particle production. The model is an attempt to evade the coincidence and cosmological constant problems of the standard model ($\Lambda$CDM) and also…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-05 J. A. S. Lima , S. Basilakos , F. E. M. Costa

Creation of Cold Dark Matter (CCDM), in the context of Einstein Field Equations, leads to a negative creation pressure, which can be used to explain the accelerated expansion of the Universe. Recently, it has been shown that the dynamics of…

Cosmology and Nongalactic Astrophysics · Physics 2016-01-20 J. F. Jesus , F. Andrade-Oliveira

We show that a cosmology driven by gravitationally induced particle production of all non-relativistic species existing in the present Universe mimics exactly the observed flat accelerating $\Lambda$CDM cosmology with just one dynamical…

General Relativity and Quantum Cosmology · Physics 2016-03-23 J. A. S. Lima , R. C. Santos , J. V. Cunha

In this work the results from the quantum process of matter creation have been used in order to constrain the mass of the dark matter particles in an accelerated Cold Dark Matter model (Creation Cold Dark Matter, CCDM). In order to take…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-19 J. F. Jesus , S. H. Pereira

Cold Dark Matter (CDM) has become the standard modern theory of cosmological structure formation. Its predictions appear to be in good agreement with data on large scales, and it naturally accounts for many properties of galaxies. But…

Astrophysics · Physics 2009-11-07 Joel R. Primack

We discuss the dynamics of the universe within the framework of Massive Graviton Dark Matter scenario (MGCDM) in which gravitons are geometrically treated as massive particles. In this modified gravity theory, the main effect of the…

Cosmology and Nongalactic Astrophysics · Physics 2011-05-13 S. Basilakos , M. Plionis , M. E. S. Alves , J. A. S. Lima

The galaxy cluster power spectrum and mass/temperature functions are currently the most precise observational tools for constraining the theory of the formation of large scale structure (LSS) in the Universe. Complementing these tests by…

Astrophysics · Physics 2007-05-23 V. N. Lukash

Cosmological models with a positive cosmological constant and $\Omega_0<1$ have a number of attractive features. A larger Hubble constant, which can be compatible with the recent HST estimate, and a large fraction of baryon density in…

Astrophysics · Physics 2007-05-23 Anatoly Klypin , Joel Primack , Jon Holtzman

Creation of Cold Dark Matter (CCDM) can macroscopically be described by a negative pressure, and, therefore, the mechanism is capable to accelerate the Universe, without the need of an additional dark energy component. In this framework we…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-28 J. F. Jesus , F. A. Oliveira , S. Basilakos , J. A. S. Lima

Motivated by inflation, the theory of big-bang nucleosynthesis and the quest for a deeper understanding of the fundamental forces and particles, a very successful paradigm for the development of structure in the Universe has evolved. It…

Astrophysics · Physics 2009-10-28 Scott Dodelson , Evalyn Gates , Michael S. Turner

On the basis of a previously established scalar-tensor extension of the $\Lambda$CDM model we develop an effective fluid approach for the matter growth function. This extended $\Lambda$CDM (henceforth $e_{\Phi}\Lambda$CDM) cosmology takes…

Cosmology and Nongalactic Astrophysics · Physics 2019-05-01 W. Zimdahl , H. E. S. Velten , W. C. Algoner

We present results of large N-body-hydrodynamic simulations of galaxy formation. Our simulations follow the formation of galaxies in cubic volumes of side 100Mpc, in two versions of the cold dark matter (CDM) cosmogony: the standard,…

The bulk viscosity of cosmological fluid and the creation of cold dark matter both result in the generation of irreversible entropy (related to dissipative processes) in a homogeneous and isotropic universe. To consider such effects, the…

Cosmology and Nongalactic Astrophysics · Physics 2014-12-16 Nobuyoshi Komatsu , Shigeo Kimura

Cosmologies including continuous matter creation are able to reproduce the main properties of the standard $\Lambda$CDM model, in particular in cases where the particle and entropy production rates are equal. These specific models,…

General Relativity and Quantum Cosmology · Physics 2011-03-07 Alain de Roany , J. A. de Freitas Pacheco

The Standard Cosmological Model has experienced tremendous success at reproducing observational data by assuming a universe dominated by a cosmological constant and dark matter in a flat geometry. However, several studies, based on local…

Cosmology and Nongalactic Astrophysics · Physics 2022-11-29 Jailson S. Alcaniz , Jacinto P. Neto , Farinaldo S. Queiroz , Deivid R. da Silva , Raimindo Silva
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