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We report a series of high-resolution cosmological N-body simulations designed to explore the formation and properties of dark matter halos with masses close to the damping scale of the primordial power spectrum of density fluctuations. We…

Astrophysics · Physics 2009-11-13 P. Colin , O. Valenzuela , V. Avila-Reese

Current models of galaxy formation applied to understanding the large-scale structure of the universe have two parts. The first is an accurate solution of the equations of motion for the dark matter due to gravitational clustering. The…

Astrophysics · Physics 2009-11-06 Roman Scoccimarro , Ravi K. Sheth

Shape measurements of galaxies and galaxy clusters are widespread in the analysis of cosmological simulations. But the limitations of those measurements have been poorly investigated. In this paper, we explain why the quality of the shape…

Astrophysics of Galaxies · Physics 2023-02-22 Moritz S. Fischer , Lucas M. Valenzuela

In this study, we investigate the problem of tracking objects with unknown shapes using three-dimensional (3D) point cloud data. We propose a Gaussian process-based model to jointly estimate object kinematics, including position,…

Signal Processing · Electrical Eng. & Systems 2021-04-12 Murat Kumru , Emre Özkan

We propose a lightweight deep convolutional neural network (lCNN) to estimate cosmological parameters from simulated three-dimensional dark matter (DM) halo distributions and associated statistics. The training dataset comprises 2000…

Cosmology and Nongalactic Astrophysics · Physics 2024-09-20 Zhiwei Min , Xu Xiao , Jiacheng Ding , Liang Xiao , Jie Jiang , Donglin Wu , Qiufan Lin , Yang Wang , Shuai Liu , Zhixin Chen , Xiangru Li , Jinqu Zhang , Le Zhang , Xiao-Dong Li

We use network theory to study topological features in the hierarchical clustering of dark matter halos. We use public halo catalogs from cosmological N-body simulations and construct tree graphs that connect halos within main halo systems.…

Cosmology and Nongalactic Astrophysics · Physics 2024-03-22 Daneng Yang , Hai-Bo Yu

We review the formalism and applications of the halo-based description of nonlinear gravitational clustering. In this approach, all mass is associated with virialized dark matter halos; models of the number and spatial distribution of the…

Astrophysics · Physics 2011-07-19 Asantha Cooray , Ravi Sheth

Conservative mass limits are often imposed on the dark matter halo catalogues extracted from N-body simulations. By comparing simulations with different mass resolutions, at $z=0$ we find that even for halos resolved by 100 particles, the…

Cosmology and Nongalactic Astrophysics · Physics 2021-12-08 Joaquin Armijo , Carlton M. Baugh , Nelson D. Padilla , Peder Norberg , Christian Arnold

The accurate characterisation of the 3D deformations of slender fibres and thin sheets in flow, is a key experimental challenge in the study of particle-laden flows. We propose a high-resolution, single-camera method to visualise…

Fluid Dynamics · Physics 2026-03-18 Tymoteusz Miara , Draga Pihler-Puzović , Matthias Heil , Anne Juel

The phase space structure of dark matter halos can be used to measure the mass of the halo, infer mass accretion rates, and probe the effects of modified gravity. Previous studies showed that the splashback radius can be measured in…

Cosmology and Nongalactic Astrophysics · Physics 2021-02-23 Han Aung , Daisuke Nagai , Eduardo Rozo , Rafael Garcia

We have found that the phase-space of a dark matter particles assembling a galactic halo in cosmological N-body simulations has well defined fine grained structure. Recently accreted particles form distinctive velocity streams with high…

Astrophysics of Galaxies · Physics 2015-06-11 K. Dolag , A. D. Dolgov , I. I. Tkachev

Dark matter substructures are interesting since they can reveal the properties of dark matter. Collisionless N-body simulations of cold dark matter show more substructures compared with the population of dwarf galaxy satellites observed in…

Cosmology and Nongalactic Astrophysics · Physics 2020-10-28 Joshua Yao-Yu Lin , Hang Yu , Warren Morningstar , Jian Peng , Gilbert Holder

We compare the dark matter halos' structural parameters derived for four Milky Way dwarf spheroidal galaxies to those of subhalos found in cosmological $N$-body simulations. We confirm that estimates of the mass at a single fixed radius are…

Astrophysics of Galaxies · Physics 2015-12-02 Maarten A. Breddels , Carlos Vera-Ciro , Amina Helmi

We consider the problem of finding an accurate representation of neuron shapes, extracting sub-cellular features, and classifying neurons based on neuron shapes. In neuroscience research, the skeleton representation is often used as a…

Computer Vision and Pattern Recognition · Computer Science 2022-12-15 Jiaxiang Jiang , Michael Goebel , Cezar Borba , William Smith , B. S. Manjunath

We train graph neural networks on halo catalogues from Gadget N-body simulations to perform field-level likelihood-free inference of cosmological parameters. The catalogues contain $\lesssim$5,000 halos with masses $\gtrsim…

3D shape is a crucial but heavily underutilized cue in today's computer vision systems, mostly due to the lack of a good generic shape representation. With the recent availability of inexpensive 2.5D depth sensors (e.g. Microsoft Kinect),…

Computer Vision and Pattern Recognition · Computer Science 2015-04-16 Zhirong Wu , Shuran Song , Aditya Khosla , Fisher Yu , Linguang Zhang , Xiaoou Tang , Jianxiong Xiao

Explicitly covariant analytical expressions are derived that describe the boundaries of shadows cast by massive particles scattered by a gravitating object. This covers scenarios with particles having effectively variable mass, such as…

General Relativity and Quantum Cosmology · Physics 2023-12-15 Kirill Kobialko , Igor Bogush , Dmitri Gal'tsov

The density profiles of dark matter haloes can potentially probe dynamics, fundamental physics, and cosmology, but some of the most promising signals reside near or beyond the virial radius. While these scales have recently become…

Cosmology and Nongalactic Astrophysics · Physics 2022-04-29 Benedikt Diemer

Based on a set of cosmological N-body simulations we analyze properties of the dark matter haloes (DM) in a galaxy mass range ($10^{11} - 10^{13} h^{-1}M_{\odot}$) in modified $\lcdm$ cosmology with additional dynamically screened scalar…

Cosmology and Nongalactic Astrophysics · Physics 2010-08-31 Wojciech A. Hellwing

Spectral shape descriptors have been used extensively in a broad spectrum of geometry processing applications ranging from shape retrieval and segmentation to classification. In this pa- per, we propose a spectral graph wavelet approach for…

Graphics · Computer Science 2017-05-18 Majid Masoumi , A. Ben Hamza