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We use a set of cosmological N-body simulations to investigate the structural shape of galaxy-sized cold dark matter (CDM) halos. Unlike most previous work on the subject - which dealt with shapes as measured by the inertia tensor - we…

Astrophysics · Physics 2008-11-26 E. Hayashi , J. F. Navarro , V. Springel

We present a dual-stage neural network architecture for analyzing fine shape details from microscopy recordings in 3D. The system, tested on red blood cells, uses training data from both healthy donors and patients with a congenital blood…

Quantitative Methods · Quantitative Biology 2020-05-29 G. Simionato , K. Hinkelmann , R. Chachanidze , P. Bianchi , E. Fermo , R. van Wijk , M. Leonetti , C. Wagner , L. Kaestner , S. Quint

We investigate the evolution of dark matter halo shapes in cosmological N-body simulations both in scale free Einstein-De Sitter (EdS) and $\Lambda$CDM cosmologies. We compute the axis ratios ($q=b/a,s=c/a$) of well resolved central halos…

Cosmology and Nongalactic Astrophysics · Physics 2026-04-03 Ayan Nanda , Nishikanta Khandai , J. S. Bagla , Swati Gavas

For the last 30 years many observational and theoretical evidences have shown that galaxy clusters are not spherical objects, and that their shape is much better described by a triaxial geometry. With the advent of multi-wavelength data of…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-23 Mario Bonamigo , Giulia Despali , Marceau Limousin , Raul Angulo , Carlo Giocoli , Geneviève Soucail

Estimating the ellipticity of dark matter haloes at the galaxy or galaxy-cluster scale can provide important constraints on the formation of galaxies or clusters, as well as on the nature of dark matter. We show in this paper that the…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-11 Xinzhong Er , Matthias Bartelmann

We develop a phenomenological model to predict the clustering of dark matter halos on the light-cone by combining several existing theoretical models. Assuming that the velocity field of halos on large scales is approximated by linear…

Astrophysics · Physics 2015-06-24 Takashi Hamana , Naoki Yoshida , Yasushi Suto , August E. Evrard

We derive inner dark matter halo density profile slopes for a sample of 200 dwarf galaxies by inverting rotation curves obtained from high-quality, long-slit optical spectra. Using simulations to assess the impact of long-slit observing and…

Astrophysics · Physics 2007-05-23 K. Spekkens , R. Giovanelli

In this work, we expand and test the capabilities of our recently developed super-resolution (SR) model to generate high-resolution (HR) realizations of the full phase-space matter distribution, including both displacement and velocity,…

Cosmology and Nongalactic Astrophysics · Physics 2021-09-20 Yueying Ni , Yin Li , Patrick Lachance , Rupert A. C. Croft , Tiziana Di Matteo , Simeon Bird , Yu Feng

Herein, we present a deep-learning technique for reconstructing the dark-matter density field from the redshift-space distribution of dark-matter halos. We built a UNet-architecture neural network and trained it using the COmoving…

Cosmology and Nongalactic Astrophysics · Physics 2023-12-21 Zitong Wang , Feng Shi , Xiaohu Yang , Qingyang Li , Yanming Liu , Xiaoping Li

We propose an automatic algorithm for 3D inverse electromagnetic scattering based on the combination of topological derivatives and regularized Gauss-Newton iterations. The algorithm is adapted to decoding digital holograms. A hologram is a…

Optics · Physics 2019-04-01 A. Carpio , T. G. Dimiduk , F. Le Louer , M. L. Rapun

We use N-body/gasdynamical LambdaCDM cosmological simulations to examine the effect of the assembly of a central galaxy on the shape and mass profile of its dark halo. Two series of simulations are compared; one that follows only the…

Astrophysics of Galaxies · Physics 2015-05-13 Mario G. Abadi , Julio F. Navarro , Mark Fardal , Arif Babul , Matthias Steinmetz

We propose a new hologram representation based on structured complex-valued 2D Gaussian primitives, which replaces per-pixel information storage and reduces the parameter search space by up to 10:1. To enable end-to-end training, we develop…

Computer Vision and Pattern Recognition · Computer Science 2025-11-20 Yicheng Zhan , Xiangjun Gao , Long Quan , Kaan Akşit

We describe the first results from two observational projects aimed at measuring the amount and spatial distribution of dark matter in distant early-type galaxies (E/S0s) and clusters of galaxies. At the galaxy scale, the Lenses Structure…

Astrophysics · Physics 2007-05-23 T. Treu , L. V. E. Koopmans , D. J. Sand , G. P. Smith , R. S. Ellis

We give an analytical form for the weighted correlation function of peaks in a Gaussian random field. In a cosmological context, this approach strictly describes the formation bias and is the main result here. Nevertheless, we show its…

Cosmology and Nongalactic Astrophysics · Physics 2022-01-24 Licia Verde , Raul Jimenez , Fergus Simpson , Luis Alvarez-Gaume , Alan Heavens , Sabino Matarrese

We have identified over 2000 well resolved cluster halos, and also their associated bound subhalos, from the output of a 1024^3 particle cosmological N-body simulation (of box size 320 h^-1 Mpc and softening length 3.2 h^-1 kpc). This has…

Astrophysics · Physics 2010-11-11 L. D. Shaw , J. Weller , J. P. Ostriker , P. Bode

Despite being a fundamental property of galaxies that dictates the form of the potential, the 3D shape is intrinsically difficult to determine from observations. The improving quality of triaxial modeling methods in recent years has made it…

Astrophysics of Galaxies · Physics 2024-10-16 Lucas M. Valenzuela , Rhea-Silvia Remus , Klaus Dolag , Benjamin A. Seidel

Impressive progress in 3D shape extraction led to representations that can capture object geometries with high fidelity. In parallel, primitive-based methods seek to represent objects as semantically consistent part arrangements. However,…

Computer Vision and Pattern Recognition · Computer Science 2021-03-19 Despoina Paschalidou , Angelos Katharopoulos , Andreas Geiger , Sanja Fidler

We use N-body simulations of dark matter haloes in cold dark matter (CDM) and a large set of different warm dark matter (WDM) cosmologies to demonstrate that the spherically averaged density profile of dark matter haloes has a shape that…

Astrophysics of Galaxies · Physics 2015-05-20 E. Polisensky , M. Ricotti

We propose a new recursive method for simultaneous estimation of both the pose and the shape of a three-dimensional extended object. The key idea of the presented method is to represent the shape of the object using spherical harmonics,…

Robotics · Computer Science 2020-12-29 Gerhard Kurz , Florian Faion , Florian Pfaff , Antonio Zea , Uwe D. Hanebeck

We report a series of high-resolution N-body simulations designed to examine the internal physical properties of dark matter halos. A total of fifteen halos, each represented by $\sim 1$ million particles within the virial radius, have been…

Astrophysics · Physics 2009-09-25 Y. P. Jing , Yasushi Suto