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The probability distribution functions (PDF) of density of the ISM in galactic disks and global star formation rate are discussed. Three-dimensional hydrodynamic simulations show that the PDFs in globally stable, inhomogeneous ISM in…

Astrophysics · Physics 2011-02-11 Keiichi Wada , Colin Norman

The probability distribution functions (PDFs) for atomic, molecular, and total gas surface densities of M33 are determined at a resolution of about 50~pc over regions that share coherent morphological properties to unveil fingerprints of…

Astrophysics of Galaxies · Physics 2018-10-03 Edvige Corbelli , Bruce G. Elmegreen , Jonathan Braine , David Thilker

We derive an analytical theory of the PDF of density fluctuations in supersonic turbulence in the presence of gravity in star-forming clouds. The theory is based on a rigorous derivation of a combination of the Navier-Stokes continuity…

Astrophysics of Galaxies · Physics 2020-11-11 Etienne Jaupart , Gilles Chabrier

We study the probability distribution function (PDF) of the mass density in simulations of supersonic turbulence with properties appropriate for molecular clouds. For this study we use Athena, a new higher-order Godunov code. We find there…

Astrophysics · Physics 2008-09-23 M. Nicole Lemaster , James M. Stone

We investigate the evolution of axis ratios of triaxial haloes using the phase space description of triaxial collapse. In this formulation, the evolution of the triaxial ellipsoid is described in terms of the dynamics of eigenvalues of…

Cosmology and Nongalactic Astrophysics · Physics 2018-03-14 Sharvari Nadkarni-Ghosh , Bhaskar Arya

The purpose of the present paper is to derive a partial differential equation (PDE) for the single-time single-point probability density function (PDF) of the velocity field of a turbulent flow. The PDF PDE is a highly non-linear…

Mathematical Physics · Physics 2021-07-08 Jiawei Li , Zhongmin Qian , Mingrui Zhou

A probabilistic description is essential for understanding growth processes far from equilibrium. In this paper, we compute time-dependent Probability Density Functions (PDFs) in order to investigate stochastic logistic and Gompertz models,…

Adaptation and Self-Organizing Systems · Physics 2017-12-08 Lucille-Marie Tenkès , Rainer Hollerbach , Eun-jin Kim

A recent study by Wang {\it et al.}(arXiv:2309.01417) proposed a novel connection between the nature of the parton distribution function (PDF) and the characteristics of its moments. In this study, we apply these findings to analyze the…

High Energy Physics - Phenomenology · Physics 2024-07-16 Xiaobin Wang , Zexin Wu , Minghui Ding , Lei Chang

We derive cosmological constraints from the probability distribution function (PDF) of evolved large-scale matter density fluctuations. We do this by splitting lines of sight by density based on their count of tracer galaxies, and by…

We study how primordial non-Gaussianity affects the pairwise velocity probability density function (PDF) using an analytical model and cosmological N-body simulations. We adopt the local type non-Gaussian models characterized by f_{nl}, and…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-19 Tsz Yan Lam , Takahiro Nishimichi , Naoki Yoshida

Weak lensing measurements are starting to provide statistical maps of the distribution of matter in the universe that are increasingly precise and complementary to cosmic microwave background maps. The probability distribution (PDF)…

Astrophysics · Physics 2009-11-10 Tong-Jie Zhang , Ue-Li Pen

A step by step procedure to derive analytically the exact dynamical evolution equations of the probability density functions (PDF) of well known kinetic wealth exchange economic models is shown. This technique gives a dynamical insight into…

General Finance · Quantitative Finance 2015-05-20 Xavier Calbet , Jose-Luis Lopez , Ricardo Lopez-Ruiz

We study local power fluctuations in numerical simulations of stationary, homogeneous, isotropic turbulence in two and three dimensions with Gaussian forcing. Due to the near-Gaussianity of the one-point velocity distribution, the…

Statistical Mechanics · Physics 2009-11-13 M. M. Bandi , Sergei G. Chumakov , Colm Connaughton

The Velocity Gradients Technique (VGT) and the Probability Density Functions (PDFs) of mass density are tools to study turbulence, magnetic fields, and self-gravity in molecular clouds. However, self-absorption can significantly make the…

Astrophysics of Galaxies · Physics 2021-01-20 Yue Hu , A. Lazarian

Statistical analyses of finite sample distributions usually assume that fluctuations are self-averaging, i.e. that they are statistically similar in different regions of the given sample volume. By using the scale-length method, we test…

Cosmology and Nongalactic Astrophysics · Physics 2010-11-02 Francesco Sylos Labini , Nikolay L. Vasilyev , Yurij V. Baryshev

We conduct numerical experiments to determine the density probability distribution function (PDF) produced in supersonic, isothermal, self-gravitating turbulence of the sort that is ubiquitous in star-forming molecular clouds. Our…

Astrophysics of Galaxies · Physics 2021-08-10 Shivan Khullar , Christoph Federrath , Mark R. Krumholz , Christopher D. Matzner

The normal distribution is used as a unified probability distribution, however, our researcher found that it is not good agreed with the real-life dynamical system's data. We collected and analyzed representative naturally occurring data…

Dynamical Systems · Mathematics 2020-11-06 Wei Ping Cheng , Zhi Hong Zhang , Pu Wang

During the evolution of density inhomogeneties in an $\Omega=1$, matter dominated universe, the typical density contrast changes from $\delta\simeq 10^{-4}$ to $\delta\simeq 10^2$. However, during the same time, the typical value of the…

General Relativity and Quantum Cosmology · Physics 2019-08-17 J. S. Bagla , T. Padmanabhan

Probability density functions (PDFs) of scale-dependent energy fluctuations, $P[\delta E(\ell)]$, are studied in high-resolution direct numerical simulations of Navier-Stokes and incompressible magnetohydrodynamic (MHD) turbulence. MHD…

Fluid Dynamics · Physics 2009-11-13 Mahdi Momeni , Wolf-Christian Müller

I study the role of shear fields by using an analytical approximate solution for the equations of motion of homogeneous ellipsoids embedded in a homogeneous background. The equations of motion of a homogeneous ellipsoid (Icke 1973; White &…

Astrophysics · Physics 2009-11-07 A. Del Popolo
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