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The evolution of density perturbations is analysed in a modified theory of gravity with a nonminimal coupling between curvature and matter. We consider the broken degeneracy between the choices of matter Lagrangian for a perfect fluid,…

General Relativity and Quantum Cosmology · Physics 2026-01-26 Miguel Barroso Varela , Orfeu Bertolami

We perform high resolution ray-tracing simulations to investigate probability distribution functions (PDFs) of lensing convergence, shear, and magnification on distant sources up to the redshift of $z_s=20$. We pay particular attention to…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-28 Ryuichi Takahashi , Masamune Oguri , Masanori Sato , Takashi Hamana

Cosmological perturbation theory provides a fundamental framework for analyzing the evolution of density fluctuations and gravitational potentials in the Universe. It plays a crucial role in understanding large-scale structure formation and…

Cosmology and Nongalactic Astrophysics · Physics 2025-11-14 Seokcheon Lee

Cosmological Perturbation Theory (PT) is a useful tool to study the cumulants of the density and velocity fields in the large scale structure of the Universe. In Papers I & II of this series we saw that the Spherical Collapse (SC) model…

Astrophysics · Physics 2009-10-30 P. Fosalba , E. Gaztanaga

We compute the one-point PDF of an initially Gaussian dark matter density field using spherical collapse (SC). We compare the results to other forms available in the literature and also compare the PDFs in the $\Lambda$CDM model with an…

Cosmology and Nongalactic Astrophysics · Physics 2020-09-08 Ankush Mandal , Sharvari Nadkarni-Ghosh

We investigate how the consistency relations of large-scale structures are modified when the initial density field is not Gaussian. We consider both scenarios where the primordial density field can be written as a nonlinear functional of a…

Cosmology and Nongalactic Astrophysics · Physics 2018-01-22 Patrick Valageas , Atsushi Taruya , Takahiro Nishimichi

Using a gauge-invariant formalism we derive and solve the perturbed cosmological equations for the BSBM theory of varying fine structure 'constant'. We calculate the time evolution of inhomogeneous perturbations of the fine structure…

General Relativity and Quantum Cosmology · Physics 2009-11-07 John D. Barrow , D. F. Mota

We present an analytical description of the probability distribution function (PDF) of the smoothed three-dimensional matter density field for modified gravity and dark energy. Our approach, based on the principles of Large Deviations…

Cosmology and Nongalactic Astrophysics · Physics 2022-04-05 Matteo Cataneo , Cora Uhlemann , Christian Arnold , Alex Gough , Baojiu Li , Catherine Heymans

The vorticity random field of turbulent flow is singled out as the main dynamical variable for the description of turbulence, and the evolution equation of the probability density function (PDF) of the vorticity field has been obtained.…

Fluid Dynamics · Physics 2022-02-23 Jiawei Li , Zhongmin Qian , Mingrui Zhou

The phenomenology of velocity statistics in turbulent flows, up to now, relates to different models dealing with either signed or unsigned longitudinal velocity increments, with either inertial or dissipative fluctuations. In this paper, we…

Statistical Mechanics · Physics 2007-05-23 L. Chevillard , B. Castaing , E. Leveque , A. Arneodo

Supersonic turbulence occurs in many environments, particularly in astrophysics. In the crucial case of isothermal turbulence, the probability density function (PDF) of the logarithmic density, $s$, is well measured, but a theoretical…

Astrophysics of Galaxies · Physics 2024-10-31 Evan Scannapieco , Liubin Pan , Edward Buie , Marcus Brüggen

We calculate the relativistic constraint equation which relates the curvature perturbation to the matter density contrast at second order in cosmological perturbation theory. This relativistic "second order Poisson equation" is presented in…

Cosmology and Nongalactic Astrophysics · Physics 2014-03-13 Juan Carlos Hidalgo , Adam J. Christopherson , Karim A. Malik

We use cosmological N-body simulations to investigate whether measurements of the moments of large-scale structure can yield constraints on primordial non-Gaussianity. We measure the variance, skewness, and kurtosis of the evolved density…

Cosmology and Nongalactic Astrophysics · Physics 2014-07-24 Qingqing Mao , Andreas A. Berlind , Cameron K. McBride , Robert J. Scherrer , Roman Scoccimarro , Marc Manera

The way particles interact with turbulent structures, particularly in regions of high vorticity and strain rate, has been investigated in simulations of homogeneous turbulence and in simple flows which have a periodic or persistent…

Fluid Dynamics · Physics 2012-05-28 Michael W. Reeks

Concepts like peculiar velocity, gravitational force, and power spectrum and their interrelationships are of utmost importance in the theories of structure formation. The observational implementation of these concepts is usually based on…

Astrophysics · Physics 2009-10-31 Reza Mansouri , Sohrab Rahvar

Turbulence is essential for understanding the structure and dynamics of molecular clouds and star-forming regions. There is a need for adequate tools to describe and characterize the properties of turbulent flows. One-point probability…

Astrophysics · Physics 2008-11-26 Ralf S. Klessen

Primordial non-Gaussianity introduces a scale-dependent variation in the clustering of density peaks corresponding to rare objects. This variation, parametrized by the bias, is investigated on scales where a linear perturbation theory is…

Cosmology and Nongalactic Astrophysics · Physics 2011-04-22 Sirichai Chongchitnan , Joseph Silk

Mathematical models based on probability density functions (PDF) have been extensively used in hydrology and subsurface flow problems, to describe the uncertainty in porous media properties (e.g., permeability modelled as random field).…

Fluid Dynamics · Physics 2020-06-01 Matteo Icardi , Marco Dentz

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

Primordial, non-Gaussian perturbations can generate scale-dependent bias in the galaxy distribution. This in turn will modify correlations between galaxy positions and peculiar velocities at late times, since peculiar velocities reflect the…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-16 Yin-Zhe Ma , James E. Taylor , Douglas Scott