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The nonextensivity in a non-isothermal plasma system with the Coulombian long-range interactions is studied in the framework of Tsallis statistics. We present for first time a mathematical expression of the nonextensive parameter q based on…

Statistical Mechanics · Physics 2015-08-10 Jiulin Du

After introducing the fundamental properties of self-gravitating systems, we present an application of Tsallis' generalized entropy to the analysis of their thermodynamic nature. By extremizing the Tsallis entropy, we obtain an equation of…

Statistical Mechanics · Physics 2009-11-10 Masa-aki Sakagami , Atsushi Taruya

Weak gravitational lensing surveys are rapidly becoming important tools to probe directly the mass density fluctuations in the universe and its background dynamics. Earlier studies have shown that it is possible to model the statistics of…

Astrophysics · Physics 2009-11-07 Patrick Valageas , Andrew J. Barber , Dipak Munshi

Evaluation of gravitational theories by means of cosmological data suffers from the fact that galaxies are biased tracers of dark matter. Current bias models focus primarily on high-density regions, whereas low-density regions carry…

Cosmology and Nongalactic Astrophysics · Physics 2019-04-11 Andrew Repp , István Szapudi

It is shown by simple and straightforward considerations that discreteness of basic physical variables is, at least, essential for generalized statistical mechanics with non-logarithmic entropy to be thermodynamically applicable to…

Statistical Mechanics · Physics 2015-05-19 Sumiyoshi Abe

The use of statistical methods to model gravitational systems is crucial to physics practice, but the extent to which thermodynamics and statistical mechanics genuinely apply to these systems is a contentious issue. This paper provides new…

History and Philosophy of Physics · Physics 2025-02-04 Lorenzo Lorenzetti

The Boltzmann distribution of an ideal gas is determined by the Hamiltonian function generating single particle dynamics. Systems with higher complexity often exhibit topological constraints, which are independent of the Hamiltonian and may…

General Relativity and Quantum Cosmology · Physics 2021-07-29 Naoki Sato

We compute the bispectrum for the \IRAS PSCz catalog and find that the galaxy distribution displays the characteristic signature of gravity. Assuming Gaussian initial conditions, we obtain galaxy biasing parameters…

Astrophysics · Physics 2009-10-31 Hume A. Feldman , Joshua A. Frieman , J. N. Fry , Roman Scoccimarro

The distribution of the spin directions of galaxies has been a question in the past decade, with numerous Earth-based and space-based experiments showing that the distribution is not necessarily random. These experiments were based on…

Cosmology and Nongalactic Astrophysics · Physics 2024-04-23 Lior Shamir

The dynamics of a one-dimensional stochastic model is studied in presence of an absorbing boundary. The distribution of fluctuations is analytically characterized within the generalized van Kampen expansion, accounting for higher order…

Statistical Mechanics · Physics 2015-05-28 Claudia Cianci , Francesca Di Patti , Duccio Fanelli

A stochastic theory of gravity is described in which the metric tensor is a random variable such that the spacetime manifold is a fluctuating physical system at a certain length scale. A general formalism is described for calculating…

General Relativity and Quantum Cosmology · Physics 2008-02-03 J. W. Moffat

In this letter we study the observed distributions of rotational velocity in a sample of more than 16,000 nearby F and G dwarf stars, magnitude complete and presenting high precision $Vsin i$ measurements. We show that the velocity…

Solar and Stellar Astrophysics · Physics 2011-02-11 J. C. Carvalho , J. D. Jr. do Nascimento , R. Silva , J. R. De Medeiros

The distribution of gravitational torques and bar strengths in the local Universe is derived from a detailed study of 163 galaxies observed in the near-infrared. The results are compared with numerical models for spiral galaxy evolution. It…

Astrophysics · Physics 2009-11-07 David L. Block , Frederic Bournaud , Francoise Combes , Ivanio Puerari , Ron Buta

This paper is an attempt to study the thermodynamics of the structure formation in the large scale universe in the non local gravity using Boltzmann statistics and the Tsallis statistics. The partition function is obtained in both the…

General Relativity and Quantum Cosmology · Physics 2021-05-17 M. Hameeda , B. Pourhassan , M. C. Rocca , Aram Bahroz Brzo

We investigate the impact of nonaxisymmetric structure on estimates of galaxy inclinations and position angles. A new minimization technique is used to obtain estimates of inclination and position angle from a global fit to either…

Astrophysics · Physics 2009-11-07 Eric I. Barnes , J. A. Sellwood

We explore the mass distribution of material associated with galaxies from the observation of gravitational weak lensing for the galaxy mass correlation function with the aid of $N$-body simulations of dark matter. The latter is employed to…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-28 Shogo Masaki , Masataka Fukugita , Naoki Yoshida

Starting from the basic prescriptions of the Tsallis' nonextensive thermostatistics, i.e. generalized entropy and normalized q-expectation values, we study the relativistic nonextensive thermodynamics and derive a Boltzmann transport…

Statistical Mechanics · Physics 2015-06-24 A. Lavagno

Non-linear gravitational collapse introduces non-Gaussian statistics into the matter fields of the late Universe. As the large-scale structure is the target of current and future observational campaigns, one would ideally like to have the…

Cosmology and Nongalactic Astrophysics · Physics 2017-09-12 Elena Sellentin , Andrew H. Jaffe , Alan F. Heavens

Systems with a long-term stationary state that possess as a spatio-temporally fluctuation quantity $\beta$ can be described by a superposition of several statistics, a "super statistics". We consider first, the Gamma, log-normal and…

Statistical Mechanics · Physics 2015-06-05 O. Obregón , A. Gil-Villegas

We study the redshift distribution of two samples of early-type gravitational lenses, extracted from a larger collection of 122 systems, to constrain the cosmological constant in the LCDM model and the parameters of a set of alternative…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-05 Shuo Cao , Giovanni Covone , Zong-Hong Zhu