135 citations · 1.4k across the 81 of their papers we have counts for
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A self-gravitating system composed of baryonic and dark matter analysed from the post-Newtonian Boltzmann equations
Gilberto M. Kremer, Kamel Ourabah
We study the Jeans gravitational instability for a mixture of baryonic and dark matter particles, in the post-Newtonian approximation. We adopt a kinetic model consisting of a coup…
Relaxation-Time Model for the Post-Newtonian Boltzmann Equation
Gilberto M. Kremer
The non-equilibrium contributions to the post-Newtonian hydrodynamic equations are determined from a relaxation-time model of the post-Newtonian Boltzmann equation. The Chapman-Ens…
Stellar structure model in the post-Newtonian approximation
Gilberto Medeiros Kremer
In this work the influence of the post-Newtonian corrections to the equations of stellar structure is analysed. The post-Newtonian Lane-Emden equation follows from the correspondin…
Post-Newtonian Jeans Equation for Stationary and Spherically Symmetrical Self-Gravitating System
Gilberto M. Kremer
The post-Newtonian Jeans equation for stationary self-gravitating systems is derived from the post-Newtonian Boltzmann equation in spherical coordinates. The Jeans equation is coup…
Post-Newtonian non-equilibrium kinetic theory
Gilberto M. Kremer
The post-Newtonian hydrodynamic equations for a non-perfect fluid are developed within the framework of a post-Newtonian Boltzmann equation. The post-Newtonian components of the en…
Jeans instability in an expanding universe with dissipation
Gilberto M. Kremer
Jeans instability is analysed in an expanding universe within the framework of BGK model of the Boltzmann equation and Poisson equations. The background is characterized by a comov…
Jeans Instability from post-Newtonian Boltzmann equation
Gilberto M. Kremer
Jeans instability within the framework of post-Newtonian Boltzmann and Poisson equations are analyzed. The components of the energy-momentum tensor are calculated from a post-Newto…
Post-Newtonian Kinetic Theory
Gilberto M. Kremer
A kinetic theory for relativistic gases in the presence of gravitational fields is developed in the second post-Newtonian approximation. The corresponding Boltzmann equation is det…
Post-Newtonian Spherically Symmetrical Accretion
Gilberto M. Kremer, Leandro C. Mehret
The objetive of this work is to investigate the influence of the corrections to the spherical symmetrical accretion of an infinity gas cloud characterized by a polytropic equation…
Using kinetic theory to examine a self-gravitating system composed of baryons and cold dark matter
Gilberto M. Kremer, Martín G. Richarte, Elberth M. Schiefer
We examine the evolution of non-relativistic cold dark matter gravitationally coupled to baryons with modes deep inside the Hubble radius (sub-horizon regime) using akinetic theory…
Cosmological Solutions for the Geometrical Scalar-Tensor with the Potential Determined by the Noether Symmetry Approach
Adriano B. Barreto, Gilberto M. Kremer
In this work we consider a scale-tensor theory in which the space-time is endowed with a Weyl integrable geometrical structure due to the Palatini variational method. Since the sca…
Temperature oscillations of a gas moving close to circular geodesic in Reissner-Nordström spacetime
Leandro C. Mehret, Gilberto M. Kremer
The objective of this work is to analyze the temperature oscillations that occur in a gas in a circular motion under the action of a Reissner-Nordström gravitational field, verifyi…
Stellar structure model in hydrostatic equilibrium in the context of -gravity
Raíla André, Gilberto M. Kremer
In this work we present a stellar structure model from -gravity point of view capable to describe some classes of stars (White Dwarfs, Brown Dwarfs, Neutron stars,…
Cosmological perturbations in transient phantom inflation scenarios
Martin G. Richarte, Gilberto M. Kremer
We present a model of inflation where the inflaton is accommodated as a phantom field which exhibits an initial transient pole behavior and then decays into a quintessence field wh…
Cosmological model with fermion and tachyon fields interacting via Yukawa-type potential
Marlos O. Ribas, Fernando P. Devecchi, Gilberto M. Kremer
A model for the universe with tachyonic and fermionic fields interacting through a Yukawa-type potential is investigated. It is shown that the tachyonic field answers for the initi…
The van der Waals fluid and its role in cosmology
Rudinei C. S. Jantsch, Marcus H. B. Christmann, Gilberto M. Kremer
We analyze the properties of a generic cosmological fluid described by the van der Waals equation of state. Exact solutions for the energy density evolution are found as implicit f…
Isotropization in Bianchi type-I cosmological model with fermions and bosons interacting via Yukawa potential
M. O. Ribas, L. L. Samojeden, F. P. Devecchi +1
In this work we investigate a model for the early Universe in a Bianchi type-I metric, where the sources of the gravitational field are a fermionic and a bosonic field, interacting…
Chaplygin Gas of Tachyon Nature Imposed by Symmetry and Constrained via H(z) Data
Lucas Gardai Collodel, Gilberto Medeiros Kremer
An action of general form is proposed for a Universe containing matter, radiation and dark energy. The latter is interpreted as a tachyon field non-minimally coupled to the scalar…
Collisionless self-gravitating systems in f(R)-gravity within Palatini approach and relativistic Boltzmann equation in the Newtonian approach
Raíla André, Gilberto M. Kremer
In this work we analyze the dynamics of collisionless self-gravitating systems described by the f(R)-gravity and Boltzmann equation in the weak field approximation, focusing on the…
Non-minimally coupled tachyon field with Noether symmetry under the Palatini approach
Lucas Gardai Collodel, Gilberto Medeiros Kremer
A model for a homogeneous, isotropic, flat Universe composed by dark energy and matter is investigated. Dark energy is considered to behave as a tachyon field, which is non-minimal…
Temperature oscillations of a gas in circular geodesic motion in the Schwarzschild field
Winfried Zimdahl, Gilberto M. Kremer
We investigate a Boltzmann gas at equilibrium with its center of mass moving on a circular geodesics in the Schwarzschild field. As a consequence of Tolman's law we find that a cen…
Fermion field as inflaton, dark energy and dark matter
Guilherme Grams, Rudinei C. de Souza, Gilberto M. Kremer
The search for constituents that can explain the periods of accelerating expansion of the Universe is a fundamental topic in cosmology. In this context, we investigate how fermioni…
Exit from accelerated regimes by symmetry breaking in a universe filled with fermionic and bosonic sources
Marlos O. Ribas, Pedro Zambianchi, Fernando P. Devecchi +1
In this work we investigate a universe filled with a fermionic field and a complex scalar field, exchanging energy through a Yukawa potential; the model encodes a symmetry breaking…
Diffusion of relativistic gas mixtures in gravitational fields
Gilberto M. Kremer
A mixture of relativistic gases of non-disparate rest masses in a Schwarzschild metric is studied on the basis of a relativistic Boltzmann equation in the presence of gravitational…