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We quantitatively study the probability distribution function (PDF) of cosmological nonlinear density fluctuations from N-body simulations with Gaussian initial condition. In particular, we examine the validity and limitations of one-point…

Astrophysics · Physics 2009-11-06 Issha Kayo , Atsushi Taruya , Yasushi Suto

We develop a non-perturbative method to derive the probability distribution $P(\delta_R)$ of the density contrast within spherical cells in the quasi-linear regime. Indeed, since this corresponds to a rare-event limit a steepest-descent…

Astrophysics · Physics 2009-11-06 P. Valageas

The description of the abundance and clustering of halos for non-Gaussian initial conditions has recently received renewed interest, motivated by the forthcoming large galaxy and cluster surveys, which can potentially yield constraints of…

Cosmology and Nongalactic Astrophysics · Physics 2010-11-02 M. Grossi , L. Verde , C. Carbone , K. Dolag , E. Branchini , F. Iannuzzi , S. Matarrese , L. Moscardini

We analyze the non--Gaussian primordial fluctuations which are inescapably contributed by scalar fields $\Phi$ with vanishing expectation values, $\langle\Phi\rangle=0$, present during inflation in addition to the inflaton field. For…

General Relativity and Quantum Cosmology · Physics 2009-09-25 Harald F. Muller , Christoph Schmid

General conservation equations are derived for 2D dense granular flows from the Euler equation within the Boussinesq approximation. In steady flows, the 2D fields of granular temperature, vorticity and stream function are shown to be…

We study the dependence on configuration in momentum space of the primordial 3-point function of density perturbations in several different scenarios: standard slow-roll inflation, curvaton and variable decay models, ghost inflation, models…

Astrophysics · Physics 2009-07-09 Daniel Babich , Paolo Creminelli , Matias Zaldarriaga

We consider the statistics of volume fluctuations in a one-dimensional classical gas of non-interacting particles confined by a piston, and subjected to an arbitrary external potential. We show that despite the absence of interactions…

Statistical Mechanics · Physics 2008-07-29 Eric Bertin , Maxime Clusel , Peter C. W. Holdsworth

Minkowski Functionals (MFs) are topological statistics that have become one of many standard tools used for investigating the statistical properties of cosmological random fields. They have found regular use in studies of departures from…

Cosmology and Nongalactic Astrophysics · Physics 2012-09-20 Geraint Pratten , Dipak Munshi

What is the size of the most massive object one expects to find in a survey of a given volume? In this paper, we present a solution to this problem using Extreme-Value Statistics, taking into account primordial non-Gaussianity and its…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-28 Sirichai Chongchitnan , Joseph Silk

We numerically investigate non-Gaussianities in the late-time cosmological density field in Fourier space. We explore various statistics, including the two-point and three-point probability distribution function (PDF) of phase and modulus,…

Cosmology and Nongalactic Astrophysics · Physics 2022-06-14 Jian Qin , Jun Pan , Yu Yu , Pengjie Zhang

Near-Gaussian probability densities are common in many important physical applications. Here we develop an asymptotic expansion methodology for computing entropic functionals for such densities. The expansion proposed is a close relative of…

Statistics Theory · Mathematics 2016-06-29 Gordon V. Chavez , Richard Kleeman

Gaussian process is an indispensable tool in clustering functional data, owing to it's flexibility and inherent uncertainty quantification. However, when the functional data is observed over a large grid (say, of length $p$), Gaussian…

Computation · Statistics 2023-09-15 Anirban Chakraborty , Abhisek Chakraborty

The clustering of bounded data presents unique challenges in statistical analysis due to the constraints imposed on the data values. This paper introduces a novel method for model-based clustering specifically designed for bounded data.…

Methodology · Statistics 2025-05-16 Luca Scrucca

A sizeable level of non-Gaussianity in the primordial cosmological perturbations may be induced by a large trispectrum, i.e. by a large connected four-point correlation function. We compute the effect of a primordial non-Gaussian…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-14 Michele Maggiore , Antonio Riotto

The claimed detection of large amounts of substructure in lensing flux anomalies, and in Milky Way stellar stream gaps statistics, has lead to a step change in constraints on simple warm dark matter models. In this study we compute…

Cosmology and Nongalactic Astrophysics · Physics 2020-08-20 M. R. Lovell

Nonstationary non-Gaussian spatial data are common in many disciplines, including climate science, ecology, epidemiology, and social sciences. Examples include count data on disease incidence and binary satellite data on cloud mask…

Computation · Statistics 2020-11-30 Benjamin Seiyon Lee , Jaewoo Park

Astronomical data often suffer from noise and incompleteness. We extend the common mixtures-of-Gaussians density estimation approach to account for situations with a known sample incompleteness by simultaneous imputation from the current…

Instrumentation and Methods for Astrophysics · Physics 2020-09-17 Peter Melchior , Andy D. Goulding

We report constraints on primordial non-Gaussianity from the abundance of X-ray detected clusters. Our analytic prescription for adding non-Gaussianity to the cluster mass function takes into account moments beyond the skewness, and we…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-15 Sarah Shandera , Adam Mantz , David Rapetti , Steven W. Allen

This work is about a slow-fast data assimilation system under non-Gaussian noisy fluctuations. Firstly, we show the existence of a random invariant manifold for a stochastic dynamical system with non-Gaussian noise and two-time scales.…

Probability · Mathematics 2018-11-12 Yanjie Zhang , Huijie Qiao , Jinqiao Duan

Non-classical non-linear waves exist in dense gases for large specific heats at pressures and temperatures of the order of critical point values. These waves behave precisely opposite to the classical non-linear waves, with inverted…

Fluid Dynamics · Physics 2025-02-14 Ramesh Kolluru , S. V. Raghurama Rao , G. N. Sekhar