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The Jeans equations give the second moments or stresses required to support a stellar population against the gravity field. A general solution of the Jeans equations for arbitrary axisymmetric scale-free densities in flattened scale-free…

Astrophysics · Physics 2015-06-24 N. W. Evans , R. M. Häfner , P. T. de Zeeuw

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

A general solution of the Jeans equations for oblate scale-free logarithmic potentials is given. This provides all possible second velocity moments that can hold up a stellar population of flattened scale-free density against the gravity…

Astrophysics · Physics 2015-06-24 P. T. de Zeeuw , N. W. Evans , M. Schwarzschild

We present the theoretical framework to efficiently solve the Jeans equations for multi-component axisymmetric stellar systems, focusing on the scaling of all quantities entering them. The models may include an arbitrary number of stellar…

Astrophysics of Galaxies · Physics 2021-06-30 C. Caravita , L. Ciotti , S. Pellegrini

The Jeans analysis is often used to infer the total density of a system by relating the velocity moments of an observable tracer population to the underlying gravitational potential. This technique has recently been applied in the search…

Cosmology and Nongalactic Astrophysics · Physics 2014-02-21 Thomas Richardson , Malcolm Fairbairn

Due to the nonlinearity of the Euler{Poisson equations, it is possible that the nonlinear Jeans instability may lead to a faster density growing rate than the rate in the standard theory of linearized Jeans instability, which motivates us…

Analysis of PDEs · Mathematics 2022-02-15 Chao Liu , Yiqing Shi

The Jeans equations relate the second-order velocity moments to the density and potential of a stellar system. For general three-dimensional stellar systems, there are three equations and six independent moments. By assuming that the…

Astrophysics · Physics 2009-11-07 G. van de Ven , C. Hunter , E. K. Verolme , P. T. de Zeeuw

Corda, Mosquera Cuesta and Lorduy Gomez have shown that spherically symmetric stationary states can be used as a model for galaxies in the framework of the linearized R^2 gravity. Those states could represent a partial solution to the Dark…

General Relativity and Quantum Cosmology · Physics 2016-10-17 Rishabh Jain , Burra G. Sidharth , Christian Corda

In the solution of the Jeans equations for axisymmetric galaxy models the ``$b$-ansatz" is often adopted to prescribe the relation between the vertical and radial components of the velocity dispersion tensor, and close the equations.…

Astrophysics of Galaxies · Physics 2025-11-05 Leonardo De Deo , Luca Ciotti , Silvia Pellegrini

The dynamics of self-gravitating fluids is analyzed within the framework of a collisionless Boltzmann equation in the presence of gravitational fields and Poisson equation. Two cases are analyzed: a system with baryonic and dark matter in a…

Cosmology and Nongalactic Astrophysics · Physics 2017-02-06 Gilberto M. Kremer

By absorbing fluctuations into a local background, separate universe simulations provide a powerful technique to characterize the response of small-scale observables to the long-wavelength density fluctuations, for example those of the…

Cosmology and Nongalactic Astrophysics · Physics 2016-12-07 Chi-Ting Chiang , Yin Li , Wayne Hu , Marilena LoVerde

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

The study of a particle with position-dependent effective mass (pdem), within a double heterojunction is extended into the complex domain --- when the region within the heterojunctions is described by a non Hermitian ${\cal{PT}}$ symmetric…

Quantum Physics · Physics 2015-06-04 Anjana Sinha

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

The classic problem of the growth of density perturbations in an expanding Newtonian universe is revisited following the work of Bisnovatyi-Kogan and Zel'dovich. We propose a more general analytical approach: a system of free particles…

This article studies some numerical approximations of the homogenized matrix for stochastic linear elliptic partial differential equations in divergence form. We focus on the case when the underlying random field is a small perturbation of…

Numerical Analysis · Mathematics 2011-02-21 Ronan Costaouec

We study the gravitational instability of a general relativistic complex scalar field with a quartic self-interaction in an infinite homogeneous static background. This quantum relativistic Jeans problem provides a simplified framework to…

General Relativity and Quantum Cosmology · Physics 2018-10-24 Abril Suárez , Pierre-Henri Chavanis

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

The original Jaynes-Cummings model is described by a Hamiltonian which is exactly solvable. Here we extend this model by several types of interactions leading to a nonhermitian operator which doesn't satisfy the physical condition of…

Quantum Physics · Physics 2009-11-11 Y. Brihaye , A. Nininahazwe

A new simplified formula is derived for the absorption cross section of small dielectric ellipsoidal particles embedded in lossy media. The new expression leads directly to a closed form solution for the optimal conjugate match with respect…

Classical Physics · Physics 2017-09-13 Mariana Dalarsson , Sven Nordebo , Daniel Sjöberg , Richard Bayford
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