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Related papers: A Morphology--Cosmology Connection for X--Ray Clus…

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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 present a machine learning approach for estimating galaxy cluster masses, trained using both Chandra and eROSITA mock X-ray observations of 2,041 clusters from the Magneticum simulations. We train a random forest regressor, an ensemble…

Cosmology and Nongalactic Astrophysics · Physics 2019-10-14 Sheridan B. Green , Michelle Ntampaka , Daisuke Nagai , Lorenzo Lovisari , Klaus Dolag , Dominique Eckert , John A. ZuHone

We use N-body simulations to study evolution of galaxy clusters over the redshift interval 0 <= z <= 0.5 in cosmological models with a mixture of cold and hot dark matter (CHDM). Four different techniques are utilized: the cluster-cluster…

Astrophysics · Physics 2009-10-28 Charles Walter , Anatoly Klypin

We outline main arguments in favor of cosmological X-ray surveys of galaxy clusters. We summarize recent advances in our understanding of cluster physics. After a short review of past surveys, we present the scientific motivations of the…

Astrophysics · Physics 2007-05-23 Marguerite Pierre

The features and make up of the population of X-ray sources in Galactic star clusters reflect the properties of the underlying stellar environment. Cluster age, mass, stellar encounter rate, binary frequency, metallicity, and maybe other…

High Energy Astrophysical Phenomena · Physics 2020-03-18 Maureen van den Berg

We discuss our current progress in studying a sample of z>0.8 clusters of galaxies from the ROSAT Distant Cluster Survey. To date, we have Chandra observations for four of the ten clusters. We find that the morphology of two of these four…

Astrophysics · Physics 2007-05-23 B. Holden , S. A. Stanford , P. Rosati , P. Tozzi , G. Squires , S. Borgani , P. Eisenhardt

The morphology of clusters of galaxies may be described with a set of parameters which contain information about the formation and evolutionary history of these systems. In this paper we present a preliminary study of the morphological…

Astrophysics · Physics 2009-11-10 V. Strazzullo , M. Paolillo , G. Longo , E. Puddu , S. G. Djorgovski , R. R. De Carvalho , R. R. Gal

We describe the ensemble X-ray properties of high redshift clusters with emphasis on changes with respect to the local population. Cluster X-ray luminosity evolution is detected in five nearly independent surveys. The relevant issue now is…

Astrophysics · Physics 2007-05-23 J. Patrick Henry

We investigate the large-scale distribution of galaxy clusters taken from several X-ray catalogs. Different statistics of clustering like the conditional correlation function (CCF) and the minimal spanning tree (MST) as well as void…

Astrophysics · Physics 2008-05-16 A. V. Tikhonov , A. I. Kopylov , S. Gottlober , G. Yepes

We present an analysis of X-ray colour maps of the cores of clusters of galaxies, formed from the ratios of counts in different X-ray bands. Our technique groups pixels lying between contours in an adaptively-smoothed image of a cluster. We…

Astrophysics · Physics 2008-11-26 J. S. Sanders , A. C. Fabian , S. W. Allen

We put constraints on the main cosmological parameters of different spatially flat cosmological models by combining the recent clustering results of XMM-Newton soft (0.5-2 keV) X-ray sources, which have a redshift distribution with median…

Astrophysics · Physics 2009-11-10 Spyros Basilakos , Manolis Plionis

We use gas-dynamical simulations of galaxy clusters to compare their X-ray and strong lensing properties. Special emphasis is laid on mass estimates. The cluster masses range between 6 x 10^14 solar masses and 4 x 10^15 solar masses, and…

Astrophysics · Physics 2015-06-24 Matthias Bartelmann , Matthias Steinmetz

We compare X-ray and weak-lensing masses for four galaxy clusters that comprise the top-ranked shear-selected cluster system in the Deep Lens Survey. The weak-lensing observations of this system, which is associated with A781, are from the…

Using a set of ROSAT HRI deep pointings, we investigate the presence of small-scale structures in the central regions of clusters of galaxies. Our sample comprises 23 objects up to z=0.32, 13 of them known to host a cooling flow. Structures…

Astrophysics · Physics 2007-05-23 Marguerite Pierre , Jean-Luc Starck

Base on Gaia Second Data Release and the combination of nonparametric bivariate density estimation with the least square ellipse fitting, we derive the shape parameters of the sample clusters. By analyzing the dislocation of the sample…

Astrophysics of Galaxies · Physics 2021-12-08 Qingshun Hu , Yu Zhang , Ali Esamdin

Forthcoming large galaxy cluster surveys will yield tight constraints on cosmological models. It has been shown that in an idealized survey, containing > 10,000 clusters, statistical errors on dark energy and other cosmological parameters…

Astrophysics · Physics 2008-11-26 Joshua D. Younger , Zoltan Haiman , Greg L. Bryan , Sheng Wang

In gaussian theories of structure formation, the galaxy cluster abundance is an extremely sensitive probe of the density fluctuation power spectrum and of the density parameter, $\Omega$. We develop this theme by deriving and studying in…

Astrophysics · Physics 2008-02-03 James G. Bartlett

The properties of clusters of galaxies offer key insights into the assembly process of structure in the universe. Numerical simulations of cosmic structure formation in a hierarchical, dark matter dominated universe suggest that galaxy…

Astrophysics · Physics 2008-11-26 Julia M. Comerford , Priyamvada Natarajan

We have developed a model to describe two-point correlation functions of clusters of galaxies in X-ray flux-limited surveys. Our model properly takes account of nonlinear gravitational evolution of mass fluctuations, redshift-space…

Astrophysics · Physics 2009-10-31 Yasushi Suto , Kazuhiro Yamamoto , Tetsu Kitayama , Y. P. Jing

We present a new method to quantify substructures in clusters of galaxies, based on the analysis of the intensity of structures. This analysis is done in a residual image that is the result of the subtraction of a surface brightness model,…

Cosmology and Nongalactic Astrophysics · Physics 2012-02-06 Felipe Andrade-Santos , Gastão B. Lima Neto , Tatiana F. Laganá