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We use the recently completed one billion particle Via Lactea II LambdaCDM simulation to investigate local properties like density, mean velocity, velocity dispersion, anisotropy, orientation and shape of the velocity dispersion ellipsoid,…

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 develop and test an algorithm to rescale a simulated dark-matter particle distribution or halo catalogue from a standard gravity model to that of a modified gravity model. This method is based on that of Angulo & White but with some…

Cosmology and Nongalactic Astrophysics · Physics 2015-08-18 Alexander Mead , John Peacock , Lucas Lombriser , Baojiu Li

We present analysis of the evolution of dark matter halos in dense environments of groups and clusters in dissipationless cosmological simulations. The premature destruction of halos in such environments, known as the overmerging, reduces…

Astrophysics · Physics 2009-10-30 Anatoly Klypin , Stefan Gottloeber , Andrey Kravtsov , Alexei Khokhlov

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

We present a new suite of over 1,500 cosmological N-body simulations with varied Warm Dark Matter (WDM) models ranging from 2.5 to 30 keV. We use these simulations to train Convolutional Neural Networks (CNNs) to infer WDM particle masses…

Dark matter haloes form from small perturbations to the almost homogeneous density field of the early universe. Although it is known how large these initial perturbations must be to form haloes, it is rather poorly understood how to predict…

Cosmology and Nongalactic Astrophysics · Physics 2024-02-22 Daniel López-Cano , Jens Stücker , Marcos Pellejero Ibañez , Raúl E. Angulo , Daniel Franco-Barranco

We perform for the first time high-resolution zoom-in re-simulations of individual halos in the context of the Multi-coupled Dark Energy (McDE) scenario, which is characterised by the existence of two distinct dark matter particle species…

Cosmology and Nongalactic Astrophysics · Physics 2016-02-05 E. Garaldi , M. Baldi , L. Moscardini

We perform an analysis of the Cosmic Web as a complex network, which is built on a $\Lambda$CDM cosmological simulation. For each of nodes, which are in this case dark matter halos formed in the simulation, we compute 10 network metrics,…

Cosmology and Nongalactic Astrophysics · Physics 2020-08-04 Maksym Tsizh , Bohdan Novosyadlyj , Yurij Holovatch , Noam I Libeskind

Warm dark matter (WDM) has been proposed as an alternative to cold dark matter (CDM), to resolve issues such as the apparent lack of satellites around the Milky Way. Even if WDM is not the answer to observational issues, it is essential to…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-20 Lin F. Yang , Mark C. Neyrinck , Miguel A. Aragon-Calvo , Bridget Falck , Joseph Silk

Using the model for (bottom-up) hierarchical halo growth recently developed by Salvador-Sol\'e et al. (2012), we derive the typical spherically averaged density profile for haloes with several relevant masses in the concordant warm dark…

Cosmology and Nongalactic Astrophysics · Physics 2012-07-10 Jordi Viñas , Eduard Salvador-Solé , Alberto Manrique

We use explainable neural networks to connect the evolutionary history of dark matter halos with their density profiles. The network captures independent factors of variation in the density profiles within a low-dimensional representation,…

Cosmology and Nongalactic Astrophysics · Physics 2024-01-22 Luisa Lucie-Smith , Hiranya V. Peiris , Andrew Pontzen

Strong lensing provides a powerful means of investigating the nature of dark matter as it probes dark matter structure on sub-galactic scales. We present an extension of a forward modeling framework that uses flux ratios from quadruply…

Cosmology and Nongalactic Astrophysics · Physics 2019-07-30 Daniel Gilman , Simon Birrer , Tommaso Treu , Anna Nierenberg , Andrew Benson

The statistics of dark matter halos is an essential component of understanding the nonlinear evolution in modified gravity cosmology. Based on a series of modified gravity N-body simulations, we investigate the halo mass function,…

Cosmology and Nongalactic Astrophysics · Physics 2013-02-21 Youcai Zhang , Pengjie Zhang , Xiaohu Yang , Weiguang Cui

Dark matter (DM) halos form hierarchically in the Universe through a series of merger events. Cosmological simulations can represent this series of mergers as a graph-like ``tree'' structure. Previous work has shown these merger trees are…

We propose a morphological multi-scale analysis of large-scale structures obtained by computer simulations and by observations. Structures are obtained at different scales by applying a wavelet transform on the observed and simulated data.…

Astrophysics · Physics 2007-05-23 E. Lega , A. Bijaoui , J. -M. Alimi , H. Scholl

Cosmological galaxy formation simulations are still limited by their spatial/mass resolution and cannot model from first principles some of the processes, like star formation, that are key in driving galaxy evolution. As a consequence they…

Astrophysics of Galaxies · Physics 2022-03-02 Andrea V. Macciò , Mohamad Ali-Dib , Pavle Vulanović , Hind Al Noori , Fabian Walter , Nico Krieger , Tobias Buck

The formation of dark-matter halos from small cosmological perturbations generated in the early universe is a highly non-linear process typically modeled through N-body simulations. In this work, we explore the use of deep learning to…

Cosmology and Nongalactic Astrophysics · Physics 2026-05-07 Toka Alokda , Cristiano Porciani

The recent detection of a 3.5 keV X-ray line from the centres of galaxies and clusters by Bulbul et al. (2014a) and Boyarsky et al. (2014a) has been interpreted as emission from the decay of 7 keV sterile neutrinos which could make up the…

Cosmology and Nongalactic Astrophysics · Physics 2015-11-18 Sownak Bose , Wojciech A. Hellwing , Carlos S. Frenk , Adrian Jenkins , Mark R. Lovell , John C. Helly , Baojiu Li

We measure the mass function of dark matter halos in a large set of collisionless cosmological simulations of flat LCDM cosmology and investigate its evolution at z<~2. Halos are identified as isolated density peaks, and their masses are…