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This work explores the ability of computer vision algorithms to characterise dark matter haloes formed in different models of structure formation. We produce surface mass density maps of the most massive haloes in a suite of eight numerical…

Cosmology and Nongalactic Astrophysics · Physics 2017-04-19 Julian Merten , Quim Llorens , Hans Winther

At early times dark matter has a thermal velocity dispersion of unknown amplitude which, for warm dark matter models, can influence the formation of nonlinear structure on observable scales. We propose a new scheme to simulate cosmologies…

Cosmology and Nongalactic Astrophysics · Physics 2020-06-10 Jens Stücker , Oliver Hahn , Raul E. Angulo , Simon D. M. White

The shapelets method for image analysis is based upon the decomposition of localised objects into a series of orthogonal components with convenient mathematical properties. We extend the "Cartesian shapelet" formalism from earlier work, and…

Astrophysics · Physics 2009-11-10 Richard Massey , Alexandre Refregier

We present a new method for the analysis of images, a fundamental task in observational astronomy. It is based on the linear decomposition of each object in the image into a series of localised basis functions of different shapes, which we…

Astrophysics · Physics 2008-11-26 Alexandre Refregier

Continuous wavelet analysis is gaining popularity in science and engineering for its ability to analyze data across spatial and scale domains simultaneously. In this study, we introduce a wavelet-based method to identify halos and assess…

Instrumentation and Methods for Astrophysics · Physics 2024-09-17 Minxing Li , Yun Wang , Ping He

High-resolution cosmological N-body simulations are excellent tools for modelling the formation and clustering of dark matter haloes. These simulations suggest complex physical theories of halo formation governed by a set of effective…

Cosmology and Nongalactic Astrophysics · Physics 2022-06-24 Androniki Dimitriou , Christoph Weniger , Camila A. Correa

In this paper we study the triaxial properties of dark matter haloes of a wide range of masses extracted from a set of cosmological N-body simulations. We measure the shape at different distances from the halo centre (characterised by…

Cosmology and Nongalactic Astrophysics · Physics 2017-01-18 Giulia Despali , Carlo Giocoli , Mario Bonamigo , Marceau Limousin , Giuseppe Tormen

Dark matter haloes play a fundamental role in cosmological structure formation. The most common approach to model their assembly mechanisms is through N-body simulations. In this work we present an innovative pathway to predict dark matter…

Cosmology and Nongalactic Astrophysics · Physics 2020-07-15 Mauro Bernardini , Lucio Mayer , Darren Reed , Robert Feldmann

Multiresolution analysis is applied to the problem of halo identification in cosmological N-body simulations. The procedure makes use of a discrete wavelet transform known as the algorithme a trous and segmentation analysis. It has the…

Astrophysics · Physics 2009-10-31 Michael D. Seymour , Lawrence M. Widrow

We present measurements of the triaxial dark matter halo shapes and alignment correlation functions in the Millennium and Millennium-2 dark matter N-body simulations. These two simulations allow us to measure the distributions of halo…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-03 Michael D. Schneider , Carlos S. Frenk , Shaun Cole

The halo shape plays a central role in determining important observational properties of the haloes such as mass, concentration and lensing cross-sections. The triaxiality of lensing galaxy clusters has a substantial impact on the…

Cosmology and Nongalactic Astrophysics · Physics 2017-03-22 Jesús Vega-Ferrero , Gustavo Yepes , Stefan Gottlöber

The skeleton formalism aims at extracting and quantifying the filamentary structure of the universe is generalized to 3D density fields; a numerical method for computating a local approximation of the skeleton is presented and validated…

Astrophysics · Physics 2009-11-13 T. Sousbie , C. Pichon , S. Colombi , D. Novikov , D. Pogosyan

We train a novel deep learning architecture to perform likelihood-free inference on the value of the cosmological parameters from halo catalogs of the Quijote N-body simulations. Our model takes as input a halo catalog where each halo is…

Cosmology and Nongalactic Astrophysics · Physics 2025-05-23 Atrideb Chatterjee , Francisco Villaescusa-Navarro

We develop an algorithm to reconstruct the triaxial shapes of dark matter halos from the anisotropic spatial distributions of their substructures for the concordance background cosmology. First, we construct an analytic model for the…

Astrophysics · Physics 2016-08-30 Jounghun Lee , Xi Kang

We present a detailed non-spherical modeling of dark matter halos on the basis of a careful analysis of state-of-the art N-body simulations. The fitting formulae presented here form a complete and accurate description of the triaxial…

Astrophysics · Physics 2007-05-23 Y. P. Jing

We present astrophysical applications of the recently popular halo model to describe large scale structure clustering. We formulate the power spectrum, bispectrum and trispectrum of dark matter density field in terms of correlations within…

Astrophysics · Physics 2007-05-23 Asantha Cooray

We focus on the complex relationship between the shape of dark matter halos and the cosmological models underlying their formation. We used three realistic cosmological models from the Dark Energy Universe Simulation suite. They have…

Cosmology and Nongalactic Astrophysics · Physics 2024-10-30 Jean-Michel Alimi , Remy Koskas

We use N-body simulations to investigate the structure of dark halos in the standard Cold Dark Matter cosmogony. Halos are excised from simulations of cosmologically representative regions and are resimulated individually at high…

Astrophysics · Physics 2008-11-26 Julio F. Navarro , Carlos S. Frenk , Simon D. M. White

We present a method to simulate deep sky images, including realistic galaxy morphologies and telescope characteristics. To achieve a wide diversity of simulated galaxy morphologies, we first use the shapelets formalism to parametrize the…

We explore the radial alignment of subhalos in 2-dimensional projections of cosmological simulations. While most other recent studies focussed on quantifying the signal utilizing the full 3-dimensional spatial information any comparison to…

Astrophysics · Physics 2009-11-13 Alexander Knebe , Hideki Yahagi , Hiroyuki Kase , Geraint Lewis , Brad K. Gibson
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