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The fluctuations in the Cosmic Microwave Background (CMB) intensity due to the Sunyaev-Zeldovich (SZ) effect are the sum of a thermal and a kinetic contribution. Separating the two components to measure the peculiar velocity of galaxy…

We present results from a study of the X-ray cluster population that forms within the CLEF cosmological hydrodynamics simulation, a large N-body/SPH simulation of the Lambda CDM cosmology with radiative cooling, star formation and feedback.…

Accurate measurements of the mass distribution in galaxy and cluster halos are essential to test the cold dark matter (CDM) paradigm. The cosmological model predicts a universal shape for the density profile in all halos, independent of…

Astrophysics · Physics 2009-09-29 L. M. Voigt , A. C. Fabian

(Abridged) We examine the theoretical relationship between Omega_0 and substructure in galaxy clusters which are formed by the collapse of high density peaks in a gaussian random field. The radial mass distributions of the clusters are…

Astrophysics · Physics 2016-08-30 David A. Buote

In this paper, we discuss improvements of the Suto et al. (2000) model, in the light of recent theoretical developments (new theoretical mass functions, a more accurate mass-temperature relation and an improved bias model) to predict the…

Astrophysics · Physics 2009-11-23 A. Del Popolo , N. Ercan , S. Yesilyurt

We investigate the dynamical state of superclusters in Lambda cold dark matter ($\Lambda$CDM) cosmological models, where the density parameter $\Omega_0=0.2-0.4$ and $\sigma_8$ (the rms fluctuation on the $8h^{-1}$Mpc scale) is $0.7-0.9$.…

Astrophysics · Physics 2009-11-07 Mirt Gramann , Ivan Suhhonenko

We test the concordance LCDM cosmology by comparing predictions for the mean properties of galaxy clusters to observations. We use high-resolution N-body simulations of cosmic structure formation and semi-analytic models of galaxy formation…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-13 Stefan Hilbert , Simon D. M. White

We study dynamical mass measurements of galaxy clusters contaminated by interlopers and show that a modern machine learning (ML) algorithm can predict masses by better than a factor of two compared to a standard scaling relation approach.…

Cosmology and Nongalactic Astrophysics · Physics 2016-11-09 M. Ntampaka , H. Trac , D. J. Sutherland , S. Fromenteau , B. Poczos , J. Schneider

We have performed N-body simulations of poor clusters with enough particles to resolve the individual galaxies. The main cases of initial conditions are: (i) 50 equal mass galaxies; (ii) 60 galaxies with masses drawn from a Schechter…

Astrophysics · Physics 2007-05-23 Gastao B. Lima Neto , Frank W. Baier

We perform a detailed investigation of the statistical properties of the projected distribution of galaxy clusters obtained in Cold Dark Matter (CDM) models with both Gaussian and skewed primordial density fluctuations. We use N-body…

Astrophysics · Physics 2015-06-24 S. Borgani , P. Coles , L. Moscardini , M. Plionis

We present a very large high-resolution cosmological N-body simulation, the Millennium-XXL or MXXL, which uses 303 billion particles to represent the formation of dark matter structures throughout a 4.1Gpc box in a LambdaCDM cosmology. We…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-04 R. E. Angulo , V. Springel , S. D. M. White , A. Jenkins , C. M. Baugh , C. S. Frenk

Cosmological (LCDM) TreeSPH simulations of galaxy clusters have been performed, invoking star-formation, chemical evolution with non-instantaneous recycling, metal dependent radiative cooling, strong star-burst and/or AGN driven…

Astrophysics · Physics 2009-11-10 J. Sommer-Larsen , A. D. Romeo , L. Portinari

We study the large-scale velocity fields traced by galaxy clusters in numerical simulations of a box of side 960 $h^{-1}$ Mpc, and compare them with available data on real clusters. In order to test the reliability of the simulations, which…

We use the semi-analytic models of galaxy formation developed by Kauffmann, White \& Guiderdoni to generate predictions for the observed properties of cluster and group galaxies at redshifts between 0 and 0.6. We examine four sets of…

Astrophysics · Physics 2015-06-24 Guinevere Kauffmann

The cold dark matter (CDM) model of structure formation, normalized on large scales, leads to excessive pairwise velocity dispersions on small scales. In an attempt to circumvent this problem, we study three scenarios (all with $\Omega=1$)…

High Energy Physics - Phenomenology · Physics 2009-10-22 James. M. Gelb , Ben-Ami Gradwohl , Joshua A. Frieman

We compare the properties of galaxy groups extracted from the Updated Zwicky Catalogue (UZC) with those of groups extracted from N-body simulations of the local Universe, in a LambdaCDM and a tauCDM cosmology. In the simulations, the…

Astrophysics · Physics 2009-11-11 L. Casagrande , A. Diaferio

We present a comprehensive study on how perturbations due to a distribution of $\Lambda$CDM dark matter subhalos can lead to star clusters deviating from their orbits. Through a large suite of massless test particle simulations, we find…

Astrophysics of Galaxies · Physics 2021-03-03 Nicholas Pavanel , Jeremy J. Webb

Most studies of correlations between X-ray and optical properties of galaxy clusters have used the largest samples of data available, regardless of the morphological types of clusters included. Given the increasing evidence that morphology…

Astrophysics · Physics 2009-10-28 Christina M. Bird , Richard F. Mushotzky , Christopher A. Metzler

We apply updated semi-analytic galaxy formation models simultaneously to the stored halo/subhalo merger trees of the Millennium and Millennium-II simulations. These differ by a factor of 125 in mass resolution, allowing explicit testing of…

Cosmology and Nongalactic Astrophysics · Physics 2015-03-17 Qi Guo , Simon White , Michael Boylan-Kolchin , Gabriella De Lucia , Guinevere Kauffmann , Gerard Lemson , Cheng Li , Volker Springel , Simone Weinmann

We present the first self-consistently computed results on the evolution of X-ray properties of galaxy clusters in a Cold + Hot Dark Matter (CHDM) model. We have performed a hydrodynamic plus N-body simulation for the COBE-compatible CHDM…

Astrophysics · Physics 2009-10-22 Greg L. Bryan , Anatoly Klypin , Chris Loken , Michael L. Norman , Jack O. Burns
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