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Related papers: Jeans analysis in energy-momentum-squared gravity

200 papers

Dynamics and collapse of collisionless self-gravitating systems is described by the coupled collisionless Boltzmann and Poisson equations derived from $f(R)$-gravity in the weak field approximation. Specifically, we describe a system at…

General Relativity and Quantum Cosmology · Physics 2015-06-03 S. Capozziello , M. De Laurentis , I. De Martino , M. Formisano , S. D. Odintsov

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 coupled with the three Poisson equations from the post-Newtonian…

General Relativity and Quantum Cosmology · Physics 2022-03-15 Gilberto M. Kremer

We perform the dynamical system analysis of a cosmological model in the energy-momentum squared gravity (EMSG) of the form $f(T_{\mu\nu} T^{\mu\nu})=\alpha\ln({\lambda}T_{\mu\nu} T^{\mu\nu})$, which is known as energy-momentum log gravity…

General Relativity and Quantum Cosmology · Physics 2025-07-02 Giovanni Acquaviva , Nihan Katirci

We investigate the Jeans instability of a galactic disk embedded in a dynamically responsive dark halo. It is shown that the disk-halo system becomes nominally Jeans unstable. On small scales the instability is suppressed, if the Toomre…

Astrophysics · Physics 2009-11-13 O. Esquivel , B. Fuchs

We use 3D MHD simulations to investigate nonlinear development of the Parker, magneto-Jeans (MJI), and swing mechanisms in galactic disks. The model disks are local, isothermal, and begin from a vertically-stratified equilibrium. We first…

Astrophysics · Physics 2009-11-07 Woong-Tae Kim , Eve C. Ostriker , James M. Stone

An analysis of the gravitational instability in presence of dissipative effects is addressed. In particular, the standard Jeans Mechanism and the generalization in treating the Universe expansion are both analyzed when bulk viscosity…

General Relativity and Quantum Cosmology · Physics 2014-11-20 Nakia Carlevaro , Giovanni Montani

Nobel Prize laureate P.J.E. Peebles [24] has emphasized the importance and difficulties of studying the large scale clustering of matter in cosmology. Nonlinear gravitational instability plays a central role in understanding the clustering…

Mathematical Physics · Physics 2023-05-23 Chao Liu

Energy Momentum Squared Gravity (EMSG) is a cosmological model where the scale factor is non vanishing at all times and hence does not favor big bang cosmology. However, the profile of density in the radiation dominated universe shows that…

General Relativity and Quantum Cosmology · Physics 2020-01-22 S. Bhattacharjee , P. K. Sahoo

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 comoving Maxwellian distribution function and a space-time…

General Relativity and Quantum Cosmology · Physics 2022-06-01 Gilberto M. Kremer

We consider a gravitational theory with an additional non-minimal coupling between baryonic matter fields and geometry. The coupling is second order in the energy momentum tensor and can be seen as a generalization of the energy-momentum…

General Relativity and Quantum Cosmology · Physics 2021-04-19 Shahab Shahidi

Linear theory is used to determine the stability of the self-gravitating, rapidly (and nonuniformly) rotating, two-dimensional, and collisional particulate disk against small-amplitude gravity perturbations. A gas-kinetic theory approach is…

Astrophysics · Physics 2009-10-31 Evgeny Griv , Michael Gedalin , David Eichler , Chi Yuan

The Jeans criterion is one cornerstone in our understanding of gravitational fragmentation. A critical limitation of the Jeans criterion is that the background density is assumed to be a constant, which is often not true in dynamic…

Astrophysics of Galaxies · Physics 2024-01-30 Guang-Xing Li

Jeans instability is derived for the case of a low density self-gravitating gas beyond the Navier-Stokes equations. The Jeans instability criterium is shown to depend on a Burnett coefficient if the formalism is taken up to fourth order in…

Astrophysics · Physics 2009-11-10 L. S. Garcia-Colin , A. Sandoval-Villalbazo

We use a modified Einstein-Maxwell gravity to study stability of an electrostatic spherical star. Correction terms in this model are scalers which are made from contraction of Ricci tensor and electromagnetic vector potential. Our…

General Relativity and Quantum Cosmology · Physics 2023-12-05 Hossein Ghaffarnejad , Tohid Ghorbani , Firoozeh Eidizadeh

We investigate the stability of bounded self-gravitating systems in the canonical ensemble by using a thermodynamical approach. Our study extends the earlier work of Padmanabhan [Astrophys. J. Supp. 71, 651 (1989)] in the microcanonical…

Astrophysics · Physics 2009-11-06 P. -H. Chavanis

A rotating metric solution in Einstein-Gauss-Bonnet gravity with a negative cosmological constant was recently found in the Chern-Simons point. We construct a rotating thin shell gluing two spacetimes in Einstein-Gauss-Bonnet gravity, using…

General Relativity and Quantum Cosmology · Physics 2026-04-15 João D. Álvares , Tiago V. Fernandes

The macroscopic properties of compact stars in modified gravity theories can be significantly different from the general relativistic (GR) predictions. Within the gravitational context of scalar-tensor theories, with a scalar field $\phi$…

General Relativity and Quantum Cosmology · Physics 2023-12-05 Juan M. Z. Pretel , Sergio E. Jorás , Ribamar R. R. Reis , Sergio B. Duarte , José D. V. Arbañil

In the present work, we derive the motion of light in the weak-field limit of energy-momentum-squared gravity (EMSG). To do so, we introduce the post-Newtonian (PN) expansion of this modified theory of gravity. It is shown that in addition…

General Relativity and Quantum Cosmology · Physics 2022-05-25 Elham Nazari

In the energy-momentum squared gravity (EMSG), the matter energy-momentum tensor is not conserved due to nonminimal interaction between the usual and modified matter fields. For this reason, the $N$-body acceleration may host the EMSG…

General Relativity and Quantum Cosmology · Physics 2024-08-20 Elham Nazari

This paper is devoted to study the stability/instability of the expansionfree self gravitating source in the framework of Einstein Gauss-Bonnet gravity. The source has been taken as Tolman-Bondi model which is homogenous in nature. The…

General Relativity and Quantum Cosmology · Physics 2015-04-22 G. Abbas , S. Sarwar