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Related papers: The Relation Between Halo Shape, Velocity Dispersi…

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We investigate the connection between collisionless equilibria and the phase-space relation between density $\rho$ and velocity dispersion $\sigma$ found in simulations of dark matter halo formation, $F=\psd \propto r^{-\alpha}$.…

Astrophysics · Physics 2009-11-13 Eric I. Barnes , Liliya L. R. Williams , Arif Babul , Julianne J. Dalcanton

We use the clustering results obtained by Madgwick et al. (2003) for a sample of 96,791 2dF galaxies with redshift 0.01 \lt z \lt 0.15 to study the distribution of late-type and early-type galaxies within dark matter haloes of different…

Astrophysics · Physics 2009-11-07 M. Magliocchetti , C. Porciani

We study the phase-space structure of a dark-matter halo formed in a high resolution simulation of a Lambda CDM cosmology. Our goal is to quantify how much substructure is left over from the inhomogeneous growth of the halo, and how it may…

Astrophysics · Physics 2009-09-25 Amina Helmi , Simon D. M. White , Volker Springel

A dark matter halo is said to have formed when at least half its mass hass been assembled into a single progenitor. With this definition, it is possible to derive a simple but useful analytic estimate of the distribution of halo formation…

Astrophysics · Physics 2009-09-29 Carlo Giocoli , Jorge Moreno , Ravi K. Sheth , Giuseppe Tormen

In hierarchical models, the time derivative of the halo mass function may be thought of as the difference of two terms - a creation term, which describes the increase in the number of haloes of mass m from mergers of less massive objects,…

Astrophysics · Physics 2009-07-10 Jorge Moreno , Carlo Giocoli , Ravi K. Sheth

We study the properties of dark matter haloes of a LCDM model in different environments. Using the distance of the 5th nearest neighbour as an environmental density indicator, we show that haloes in a high density environment are more…

Astrophysics · Physics 2009-11-10 M. Einasto , I. Suhhonenko , P. Hein"am"aki , J. Einasto , E. Saar

The connections among galaxies, the dark matter halos where they form and the properties of the large-scale Cosmic Web still need to be completely disentangled. We use the cosmological hydrodynamical simulation TNG100 of the IllustrisTNG…

We study the dependence of the galaxy contents within halos on the halo formation time using two galaxy formation models, one being a semianalytic model utilizing the halo assembly history from a high resolution N-body simulation and the…

Astrophysics · Physics 2010-08-19 Guangtun Zhu , Zheng Zheng , W. P. Lin , Y. P. Jing , Xi Kang , Liang Gao

We study the three-dimensional and projected shapes of galaxy groups in the Sloan Digital Sky Survey Data Release 4, and examine the alignment between the orientation of the central galaxy and the spatial distribution of satellite galaxies.…

Astrophysics · Physics 2008-04-09 Yougang Wang , Xiaohu Yang , H. J. Mo , Cheng Li , Frank C. van den Bosch , Zuhui Fan , Xuelei Chen

We use a set of large cosmological N-body simulations to study the internal structure of dark matter haloes which form in scale-free models. We find that the radius r_178 corresponding to a mean interior overdensity of 178 accurately…

Astrophysics · Physics 2015-06-24 Shaun Cole , Cedric Lacey

High-resolution LCDM cosmological N-body simulations are used to study the properties of galaxy-size dark halos in different environments (cluster, void, and "field"). Halos in clusters and their surroundings have a median spin parameter…

Astrophysics · Physics 2009-11-13 V. Avila-Reese , P. Colin , S. Gottloeber , C. Firmani , C. Maulbetsch

We present evidence for halo assembly bias as a function of geometric environment. By classifying GAMA galaxy groups as residing in voids, sheets, filaments or knots using a tidal tensor method, we find that low-mass haloes that reside in…

A dark matter halo is commonly defined as a spherical overdensity of matter with respect to a reference density, such as the critical density or the mean matter density of the Universe. Such definitions can lead to a spurious…

Cosmology and Nongalactic Astrophysics · Physics 2013-03-12 Benedikt Diemer , Surhud More , Andrey Kravtsov

We explore a possible origin for the puzzling anti-correlation between the formation epoch of galactic dark-matter haloes and their environment density. This correlation has been revealed from cosmological N-body simulations and is in…

Astrophysics · Physics 2015-05-13 Oliver Hahn , Cristiano Porciani , Avishai Dekel , C. Marcella Carollo

In a previous paper, we described a new method for including detailed information about substructure in semi-analytic models of dark matter halo formation based on merger trees. In this paper, we present the basic predictions of our full…

Astrophysics · Physics 2009-11-10 James E. Taylor , Arif Babul

We have studied the dark matter (DM) distribution in a approx 10^12 h^-1 M_sun mass halo extracted from a simulation consistent with the concordance cosmology, where the physics regulating the transformation of gas into stars was allowed to…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-14 Susana E. Pedrosa , Patricia B. Tissera , Cecilia Scannapieco

Interactions such as mergers and flybys play a fundamental role in shaping galaxy morphology. Using the Horizon Run 4 cosmological N-body simulation, we studied the frequency and type of halo interactions, and their redshift evolution as a…

Cosmology and Nongalactic Astrophysics · Physics 2017-11-15 Benjamin L'Huillier , Changbom Park , Juhan Kim

The dark matter halo mass function is a key repository of cosmological information over a wide range of mass scales, from individual galaxies to galaxy clusters. N-body simulations have established that the friends-of-friends (FOF) mass…

Astrophysics · Physics 2009-06-23 Zarija Lukić , Darren Reed , Salman Habib , Katrin Heitmann

Adaptive SPH and N-body simulations were carried out to study the effect of gasdynamics on the structure of dark matter halos that result from the gravitational instability and fragmentation of cosmological pancakes. Such halos resemble…

Astrophysics · Physics 2007-05-23 Marcelo Alvarez , Paul R. Shapiro , Hugo Martel

We have carried out a comparative analysis of the properties of dark matter halos in N-body and hydrodynamical simulations. We analyze their density profiles, shapes and kinematical properties with the aim of assessing the effects that…

Astrophysics · Physics 2009-10-30 P. B. Tissera , R. Dom\ci nguez-Tenreiro