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We present a double distribution function of dark matter halos, with respect to both object mass and local over- (or under-) density. This analytical tool provides a statistical treatment of the properties of matter surrounding collapsed…

Astrophysics · Physics 2009-11-10 Vasiliki Pavlidou , Brian D. Fields

This paper describes continuous-space methodologies to estimate the collision probability, Euclidean distance and gradient between an ellipsoidal robot model and an environment surface modeled as a set of Gaussian distributions.…

Robotics · Computer Science 2025-07-31 Kshitij Goel , Wennie Tabib

In non-linear scales, the matter density distribution is not Gaussian. Consequently, the widely used two-point correlation function is not adequate anymore to capture the matter density field's entire behaviour. Among all statistics beyond…

Cosmology and Nongalactic Astrophysics · Physics 2022-04-20 Mohammad Ansari Fard , Zahra Baghkhani , Laya Ghodsi , Sina Taamoli , Farbod Hassani , Shant Baghram

We present a simple method for evaluating the nonlinear biasing function of galaxies from a redshift survey. The nonlinear biasing is characterized by the conditional mean of the galaxy density fluctuation given the underlying mass density…

Astrophysics · Physics 2009-10-31 Yair Sigad , Enzo Branchini , Avishai Dekel

We present a comparative analysis of several methods, known as local Lagrangian approximations, which are aimed to the description of the nonlinear evolution of large-scale structure. We have investigated various aspects of these…

Astrophysics · Physics 2009-11-06 Martin Makler , Takeshi Kodama , Mauricio O. Calvao

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 study the effects of substructure in the Galactic halo on direct detection of dark matter, on searches for energetic neutrinos from WIMP annihilation in the Sun and Earth, and on the enhancement in the WIMP annihilation rate in the halo.…

Astrophysics · Physics 2008-11-26 Marc Kamionkowski , Savvas M. Koushiappas

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

We consider the shape of the posterior distribution to be used when fitting cosmological models to power spectra measured from galaxy surveys. At very large scales, Gaussian posterior distributions in the power do not approximate the…

Cosmology and Nongalactic Astrophysics · Physics 2022-11-25 Benedict Bahr-Kalus , Will J. Percival , Lado Samushia

We investigate the gravitational collapse of a massive scalar field in a conformally flat, spherically symmetric spacetime within general relativity. The collapsing matter distribution is modeled using a minimally coupled homogeneous scalar…

General Relativity and Quantum Cosmology · Physics 2026-05-28 Mohamed Aarif A , Soumya Chakrabarti

I review the nature of three-dimensional collapse in the Zeldovich approximation, how it relates to the underlying nature of the three-dimensional Lagrangian manifold and naturally gives rise to a hierarchical structure formation scenario…

Cosmology and Nongalactic Astrophysics · Physics 2016-10-20 Oliver Hahn

Photometric surveys produce large-area maps of the galaxy distribution, but with less accurate redshift information than is obtained from spectroscopic methods. Modern photometric redshift (photo-z) algorithms use galaxy magnitudes, or…

Cosmology and Nongalactic Astrophysics · Physics 2016-06-15 J. Asorey , M. Carrasco Kind , I. Sevilla-Noarbe , R. J. Brunner , J. Thaler

We present a new approach to automate the spectroscopic redshift reliability assessment based on machine learning (ML) and characteristics of the redshift probability density function (PDF). We propose to rephrase the spectroscopic redshift…

Instrumentation and Methods for Astrophysics · Physics 2018-04-04 S. Jamal , V. Le Brun , O. Le Fèvre , D. Vibert , A. Schmitt , C. Surace , Y. Copin , B. Garilli , M. Moresco , L. Pozzetti

We generalize the spherical collapse model for the formation of bound objects to apply in a Universe with arbitrary positive cosmological constant. We calculate the critical condition for collapse of an overdense region and give exact…

Astrophysics · Physics 2007-05-23 Ewa L. Lokas , Yehuda Hoffman

A dark photon may kinetically mix with the Standard Model photon, leading to observable cosmological signatures. The mixing is resonantly enhanced when the dark photon mass matches the primordial plasma frequency, which depends sensitively…

Cosmology and Nongalactic Astrophysics · Physics 2020-12-11 Andrea Caputo , Hongwan Liu , Siddharth Mishra-Sharma , Joshua T. Ruderman

We introduce a novel two-step approach for estimating a probability density function (pdf) given its samples, with the second and important step coming from a geometric formulation. The procedure involves obtaining an initial estimate of…

Methodology · Statistics 2017-12-14 Sutanoy Dasgupta , Debdeep Pati , Anuj Srivastava

This work sets the non isotropic noncentral elliptical shape distributions via QR decomposition in the context of zonal polynomials, avoiding the invariant polynomials and the open problems for their computation. The new shape distributions…

Statistics Theory · Mathematics 2010-03-18 Jose A. Diaz-Garcia , Francisco J. Caro-Lopera

The molecular rearrangements of most fluids under flow and deformation do not directly follow the macroscopic strain field. In this work, we describe a phenomenological method for characterizing such non-affine deformation via the…

Soft Condensed Matter · Physics 2018-01-17 Guan-Rong Huang , Bin Wu , Yangyang Wang , Wei-Ren Chen

This paper considers a multivariate spatial random field, with each component having univariate marginal distributions of the skew-Gaussian type. We assume that the field is defined spatially on the unit sphere embedded in $\mathbb{R}^3$,…

Statistics Theory · Mathematics 2017-10-05 Alfredo Alegría , Sandra Caro , Moreno Bevilacqua , Emilio Porcu , Jorge Clarke

The probability density function (PDF) of a global measure in a large class of highly correlated systems has been suggested to be of the same functional form. Here, we identify the analytical form of the PDF of one such measure, the order…

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