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We study, both theoretically and experimentally, the transverse modulational instability of spatial stripe solitons in anisotropic nonlocal photorefractive media. We demonstrate that the instability scenarios depend strongly on the stripe…

Pattern Formation and Solitons · Physics 2009-11-10 Kristian Motzek , Friedemann Kaiser , Wen-Hen Chu , Ming-Feng Shih , Yuri Kivshar

We show that, provided the principal axes of the second velocity moment tensor of a stellar population are generally unequal and are oriented perpendicular to a set of orthogonal surfaces at each point, then those surfaces must be confocal…

Astrophysics of Galaxies · Physics 2015-11-25 N. W. Evans , J. L. Sanders , A. A. Williams , J. An , D. Lynden-Bell , W. Dehnen

Within the metric formalism of $f(R)$ theories of gravity, where $R$ is the Ricci scalar, we study the hydrostatic equilibrium structure of compact stars with the inclusion of anisotropic pressure. In particular, we focus on the $f(R)=…

General Relativity and Quantum Cosmology · Physics 2022-07-11 Juan M. Z. Pretel , Sergio B. Duarte

According to the cosmological principle, the Universe should appear isotropic, without any preferred directions, to an observer whom we may consider to be fixed in the co-moving co-ordinate system of the expanding Universe. Such an observer…

Cosmology and Nongalactic Astrophysics · Physics 2013-06-11 Ashok K. Singal

We model a compact relativistic body with anisotropic pressures in the presence of an electric field. The equation of state is barotropic with a linear relationship between the radial pressure and the energy density. Simple exact models of…

General Relativity and Quantum Cosmology · Physics 2015-06-17 P. Mafa Takisa , S. D. Maharaj

We study the bar instability in collisionless, rotating, anisotropic, stellar systems, using N-body simulations and also the matrix technique for calculation of modes with the perturbed collisionless Boltzmann equation. These methods are…

Astrophysics of Galaxies · Physics 2021-02-17 Philip G. Breen , Simon Rozier , Douglas C. Heggie , Anna Lisa Varri

Within the framework of non-local time-dependent stellar convection theory, we study in detail the effect of turbulent anisotropy on stellar pulsation stability. The results show that anisotropy has no substantial influence on pulsation…

Solar and Stellar Astrophysics · Physics 2018-08-30 C. Zhang , L. Deng , D. R. Xiong

An observer stationary with respect to comoving coordinates of the expanding universe should find the redshift distribution to be isotropic. However, a peculiar motion of the observer would introduce a dipole anisotropy in the observed…

Cosmology and Nongalactic Astrophysics · Physics 2019-07-15 Ashok K. Singal

The universe is nearly isotropic on very large scales. It is much more difficult to show that the universe is radially homogeneous (independent of distance), or equivalently, that it is isotropic about distant points. This taken as an…

Astrophysics · Physics 2009-10-28 Jeremy Goodman

Both numerical simulations and observational evidence indicate that the outer regions of galaxies and dark matter haloes are typically mildly to significantly radially anisotropic. The inner regions can be significantly non-isotropic,…

Astrophysics · Physics 2009-11-13 M. Baes , E. Van Hese

Where and under what conditions the transfer of energy between electromagnetic fields and particles takes place in the solar wind remains an open question. We investigate the conditions that promote the growth of kinetic instabilities…

In this paper, we study anisotropic Bessel potential and Besov spaces, where the anisotropy measures the extra amount of regularity in certain directions. Some basic properties of these spaces are established along with applications to…

Classical Analysis and ODEs · Mathematics 2011-03-02 Timothy Nguyen

Applying the technique of dynamical maps we study the orbital stability of test particles in the Solar System in the space (a,e,i) defined by 0.1<a<38 au, 0<e<0.9 and 0<i<180 identifying the unstable and stable regions. We find stable…

Earth and Planetary Astrophysics · Physics 2019-05-29 Tabare Gallardo

In the interstellar medium of galaxies and the intracluster gas of galaxy clusters, the charged particles making up cosmic rays are moving almost exclusively along (but not across) magnetic field lines. The resulting anisotropic transport…

Astrophysics of Galaxies · Physics 2016-08-31 Ruediger Pakmor , Christoph Pfrommer , Christine M. Simpson , Rahul Kannan , Volker Springel

The recent SDSS measured velocity distribution of satellite galaxies has been modelled in the context of MOND. We show that even when the extra constraint of adhering to the projected satellite number density profile is added, the two line…

Astrophysics · Physics 2007-12-27 Garry Angus , Benoit Famaey , Olivier Tiret , Francoise Combes , HongSheng Zhao

In this work, we investigate the emergence of compact, anisotropic stellar structures through the gravitational decoupling scheme within the framework of complete geometric deformation. The study introduces a novel synthesis of two…

General Relativity and Quantum Cosmology · Physics 2025-12-09 Z. Yousaf , Kazuharu Bamba , M. Z. Bhatti , S. Khan

We discuss the problem of using stellar kinematics of early-type galaxies to constrain the galaxies' orbital anisotropies and radial mass profiles. We demonstrate that compressing a galaxy's light distribution along the line of sight…

Astrophysics · Physics 2009-10-31 John Magorrian , David Ballantyne

The use of the tensor virial theorem (TVT) as a diagnostic of anisotropic velocity distributions in galaxies is revisited. The TVT provides a rigorous global link between velocity anisotropy, rotation and shape, but the quantities appearing…

Astrophysics · Physics 2009-11-11 James Binney

Recent released Planck data and other astronomical observations show that the universe may be anisotropic on large scales. Inspired by this, anisotropic cosmological models have been proposed. We note that the Finsler-Randers spacetime…

Cosmology and Nongalactic Astrophysics · Physics 2014-03-25 Zhe Chang , Xin Li , Hai-Nan Lin , Sai Wang

We present the first study of the isotropy of the distribution of morphological types of galaxies in the Local Universe out to around 200 Mpc using more than 60,000 galaxies from the HyperLeda database. We divide the sky into two opposite…

Astrophysics of Galaxies · Physics 2017-01-18 Behnam Javanmardi , Pavel Kroupa
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