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The Cosmological Principle posits that the Universe is isotropic on the largest scales. While widely supported, this foundational assumption remains testable. We analyse the angular distribution of over one million quasars from the…

Cosmology and Nongalactic Astrophysics · Physics 2025-07-04 Amit Mondal , Biswajit Pandey , Krishna Ghosh

Spatially referenced data often have autocovariance functions with elliptical isolevel contours, a property known as geometric anisotropy. The anisotropy parameters include the tilt of the ellipse (orientation angle) with respect to a…

Statistics Theory · Mathematics 2021-10-04 Manolis P. Petrakis , Dionissios T. Hristopulos

The explicit expression of ergotropy (a.k.a. available energy) of a classical system is known for the case when the system phase space density is continuous and with no plateaus. Here we provide the general expression of ergotropy that…

Statistical Mechanics · Physics 2026-03-31 Michele Campisi

Self-similar evolution is widely used in the theory of collisional stellar dynamics, but its applicability to systems with multiple stellar masses is not well established. We investigate the structural stability of self-similar evolution in…

Astrophysics of Galaxies · Physics 2026-04-01 Václav Pavlík

The dynamical properties of spherically symmetric galaxy models, where a Jaffe (1983) stellar density profile is embedded in a total mass density decreasing as $r^{-3}$ at large radii, are presented. The orbital structure of the stellar…

Astrophysics of Galaxies · Physics 2019-10-02 L. Ciotti , A. Mancino , S. Pellegrini

In our previous work we confirmed the reliability of the spherically symmetric Schwarzschild orbit-superposition method to recover the mass and velocity anisotropy profiles of spherical dwarf galaxies. Here we investigate the effect of its…

Astrophysics of Galaxies · Physics 2018-03-14 Klaudia Kowalczyk , Ewa L. Lokas , Monica Valluri

The existence of the Fundamental Plane (FP) imposes strong constraints on the structure and dynamics of elliptical galaxies, and thus contains important information on the processes of their formation and evolution. Here we focus on the…

Astrophysics · Physics 2009-11-07 Carlo Nipoti , Pasquale Londrillo , Luca Ciotti

In this study we investigate potential large-angle anisotropies in the angular distribution of the cosmological parameters $H_0$ (the Hubble constant) and $\Omega_m$ (the matter density) in the flat-$\Lambda$CDM framework, using the…

Cosmology and Nongalactic Astrophysics · Physics 2025-12-08 Rahima Mokeddem , Maria Lopes , Felipe Avila , Armando Bernui , Wiliam S. Hipólito-Ricaldi

Finite Sample Smeariness (FSS) has been recently discovered. It means that the distribution of sample Fr\'echet means of underlying rather unsuspicious random variables can behave as if it were smeary for quite large regimes of finite…

Statistics Theory · Mathematics 2021-03-02 Benjamin Eltzner , Shayan Hundrieser , Stephan F. Huckemann

We show that for elliptic parametric functionals whose Wulff shape is smooth and has strictly positive curvature, any surface with constant anisotropic mean curvature which is a topological sphere is a rescaling of the Wulff shape.

Differential Geometry · Mathematics 2009-09-14 Miyuki Koiso , Bennett Palmer

A combined sample of 79 high and low redshift supernovae Ia (SNe) is used to set constraints on the degree of anisotropy in the Universe out to $z\simeq1$. First we derive the global most probable values of matter density $\Omega_M $, the…

Astrophysics · Physics 2015-06-24 Tsafrir S. Kolatt , Ofer Lahav

The Sphere Covering Inequality was introduced in \cite{GM} (\emph{Invent. Math.}, 2018) as a sharp geometric inequality that provides a lower bound for the total area of two distinct surfaces of Gaussian curvature 1. These surfaces are…

Analysis of PDEs · Mathematics 2025-10-22 Changfeng Gui , Amir Moradifam

We probe the anisotropy of the large-scale structure (LSS) with the WISE-2MASS catalogue. This analysis is performed by a directional comparison of the galaxy number counts through the entire celestial sphere once systematic effects, such…

Cosmology and Nongalactic Astrophysics · Physics 2017-01-23 C. A. P. Bengaly , A. Bernui , J. S. Alcaniz , H. S. Xavier , C. P. Novaes

Cosmological density fields are assumed to be translational and rotational invariant, avoiding any special point or direction, thus satisfying the Copernican Principle. A spatially inhomogeneous matter distribution can be compatible with…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-19 Francesco Sylos Labini , Yuri V. Baryshev

We study the effects and implications of anisotropies at the scale of galaxy clusters by building an exact general relativistic model of a cluster using the inhomogeneous and anisotropic Szekeres metric. The model is built from a modified…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-18 M. A. Troxel , Austin Peel , Mustapha Ishak

Traditionally, the mass / velocity anisotropy degeneracy (MAD) inherent in the spherical, stationary, non-streaming Jeans equation has been handled by assuming a mass profile and fitting models to the observed kinematical data. Here, the…

Cosmology and Nongalactic Astrophysics · Physics 2010-02-11 Gary A. Mamon , Gwenael Boué

Some models (such as the Skyrme model, a low-energy effective field theory for QCD) suggest that the high-density matter prevailing in neutron star interiors may be significantly anisotropic. Anisotropy is known to affect the bulk…

General Relativity and Quantum Cosmology · Physics 2015-06-05 Hector O. Silva , Caio F. B. Macedo , Emanuele Berti , Luís C. B. Crispino

It was shown by E. Gluskin and V.D. Milman in [GAFA Lecture Notes in Math. 1807, 2003] that the classical arithmetic-geometric mean inequality can be reversed (up to a multiplicative constant) with high probability, when applied to…

Classical Analysis and ODEs · Mathematics 2018-10-16 Zakhar Kabluchko , Joscha Prochno , Vladislav Vysotsky

It is shown that the cuspy density distributions observed in the cores of elliptical galaxies can be realized by dissipationless gravitational collapse. The initial models consist of power-law density spheres such as $\rho\propto r^{-1}$…

Astrophysics · Physics 2009-10-31 S. Hozumi , A. Burkert , T. Fujiwara

Under nonuniform convection, the distribution of diffusive particles can exhibit dipole and quadrupole anisotropy induced by the fluid inertial and shear force, respectively. These convection-related anisotropies, unlike the Compton-Getting…

High Energy Astrophysical Phenomena · Physics 2022-10-26 Yiran Zhang , Siming Liu , Dejin Wu