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Related papers: Post-Newtonian Jeans analysis

200 papers

Relativistic cosmological perturbation analyses can be made based on several different fundamental gauge conditions. In the pressureless limit the variables in certain gauge conditions show the correct Newtonian behaviors. We consider the…

Astrophysics · Physics 2007-05-23 J. Hwang , H. Noh

A linear stability analysis has been performed onto a self-gravitating magnetized gas disk bounded by external pressure. The resulting dispersion relation is fully explained by three kinds of instability: a Parker-type instability driven by…

Astrophysics · Physics 2007-05-23 Sang Min Lee , Seung Soo Hong

Cosmological perturbations with wavelengths smaller than Hubble radius can be handled in the context of Newtonian theory with very high accuracy. The application of this Newtonian approximation, however, is restricted to nonrelativistic…

General Relativity and Quantum Cosmology · Physics 2007-05-23 Ali Nayeri , T. Padmanabhan

The Jeans instability is analyzed for dense magnetohydrodynamic plasmas with intrinsic magnetization, the latter due to collective electron spin effects. Furthermore, effects of electron tunneling as well as the Fermi pressure are included.…

Plasma Physics · Physics 2009-11-13 J. Lundin , M. Marklund , G. Brodin

A kinetic and hydrodynamic descriptions are developed in order to analyze the instabilities of a granular gas in the presence of a gravitational field. In the kinetic description the Boltzmann equation is coupled with the Poisson equation,…

Statistical Mechanics · Physics 2019-11-26 Gilberto Medeiros Kremer

We use linear analysis to examine the effect of cosmic rays (CRs) on the Parker-Jeans instability of magnetized self-gravitating gaseous disks. We adopt a slab equilibrium model in which the gravity (including self-gravity) is perpendicular…

Astrophysics · Physics 2009-11-11 Takuhito Kuwabara , Chung-Ming Ko

Both for the background world model and its linear perturbations Newtonian cosmology coincides with the zero-pressure limits of relativistic cosmology. However, such successes in Newtonian cosmology are not purely based on Newton's gravity,…

Astrophysics · Physics 2009-11-13 Jai-chan Hwang , Hyerim Noh

The spherical Jeans equation is a widely used tool for dynamical study of gravitating systems in astronomy. Here we test its efficacy in robustly weighing the mass of Milky Way analogues, given they need not be in equilibrium or even…

Astrophysics of Galaxies · Physics 2018-01-31 Prajwal R. Kafle , Sanjib Sharma , Aaron S. G. Robotham , Pascal J. Elahi , Simon P. Driver

We examine the effects of $f(R)$ gravity on Jeans analysis of collapsing dust clouds. We provide a method for testing modified gravity models by their effects on star formation as the presence of $f(R)$ gravity is found to modify the limit…

Cosmology and Nongalactic Astrophysics · Physics 2016-09-06 Jaakko Vainio , Iiro Vilja

We present a coarse-grained field theory of density fluctuations for a Newtonian self-gravitating many-body system and apply it to a homogeneous Universe with small density fluctuations. The theory treats the clustering of galaxies and…

Astrophysics · Physics 2008-12-25 Yang Zhang

The time evolution of initially balanced, rapidly rotating models for an isolated disk of highly flattened galaxies of stars is calculated. The method of direct integration of the Newtonian equations of motion of stars over a time span of…

Astrophysics · Physics 2007-05-23 Evgeny Griv , Michael Gedalin , Edward Liverts , David Eichler , Yehoshua Kimhi , Chi Yuan

The weak field limit of the nonminimally coupled Boltzmann equation is studied, and relations between the invariant Bardeen scalar potentials are derived. The Jean's criterion for instabilities is found through the modified dispersion…

General Relativity and Quantum Cosmology · Physics 2020-08-25 Cláudio Gomes

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

We develop a new approach to building cosmological models, in which small pieces of perturbed Minkowski space are joined together at reflection-symmetric boundaries in order to form a global, dynamical space-time. Each piece of this…

General Relativity and Quantum Cosmology · Physics 2016-04-12 Viraj A. A. Sanghai , Timothy Clifton

The post-Newtonian approximation is a method for solving Einstein's field equations for physical systems in which motions are slow compared to the speed of light and where gravitational fields are weak. Yet it has proven to be remarkably…

General Relativity and Quantum Cosmology · Physics 2015-05-27 Clifford M. Will

Modified gravity theories generically predict a violation of Lorentz invariance, which may lead to a modified dispersion relation for propagating modes of gravitational waves. We construct a parametrized dispersion relation that can…

General Relativity and Quantum Cosmology · Physics 2014-12-02 Saeed Mirshekari , Nicolas Yunes , Clifford M. Will

In this paper, we present extensively the observational consequences of massless dilaton theories at the post-Newtonian level. We extend previous work by considering a general model including a dilaton-Ricci coupling as well as a general…

General Relativity and Quantum Cosmology · Physics 2015-12-17 A. Hees , O. Minazzoli

When a self-gravitating disc is subject to irradiation, its propensity to fragmentation will be affected. The strength of self-gravitating disc stresses is expected to dictate disc fragmentation: as the strength of these torques typically…

Solar and Stellar Astrophysics · Physics 2015-06-12 Duncan Forgan , Ken Rice

In this Letter we have derived the Jeans length in the context of the Kaniadakis statistics. We have compared this result with the Jeans length obtained in the non-extensive Tsallis statistics and discussed the main differences between…

Cosmology and Nongalactic Astrophysics · Physics 2016-07-20 Everton M. C. Abreu , Jorge Ananias Neto , Edesio M. Barboza , Rafael C. Nunes

The general relativistic treatment of gravitation can be extended by preserving the geometrical nature of the theory but modifying the form of the coupling between curvature and stress tensors. The gravitation constant is thus replaced by…

General Relativity and Quantum Cosmology · Physics 2016-08-31 Marc-Thierry Jaekel , Serge Reynaud