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Related papers: Evolution of Cluster Morphology: X-ray data vs. CD…

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It is widely believed that structure in the Universe evolves hierarchically, as primordial density fluctuations, amplified by gravity, collapse and merge to form progressively larger systems. The structure and evolution of X-ray clusters,…

Astrophysics · Physics 2009-10-31 T. J. Ponman , D. B. Cannon , J. F. Navarro

The intrinsic shape of galaxy clusters can be obtained through a combination of X-ray and Sunyaev-Zeldovich effect observations once cosmological parameters are assumed to be known. In this paper we discuss the feasibility of modelling…

Astrophysics · Physics 2009-11-11 M. Sereno , E. De Filippis , G. Longo , M. W. Bautz

We present a new model for the X-ray properties of the intracluster medium that explicitly includes heating of the gas by the energy released during the evolution of cluster galaxies. We calculate the evolution of clusters by combining the…

Astrophysics · Physics 2009-10-31 R. G. Bower , A. J. Benson , C. G. Lacey , C. M. Baugh , S. Cole , C. S. Frenk

Recently, the observed cellular nature of the large-scale structure of the Universe with its quasi-regular pattern of superclusters and voids has been pointed out by several authors. In this paper, we investigate properties of the initial…

Astrophysics · Physics 2019-08-17 P. Frisch , J. Einasto , M. Einasto , W. Freudling , K. J. Fricke , M. Gramann , V. Saar , O. Toomet

We report on the analysis of a suite of SPH simulations (incorporating cooling and star formation) of mergers involving idealised X-ray clusters whose initial conditions resemble relaxed clusters with cool compact cores observed by Chandra…

We report on the first results from a redshift survey of a flux-limited sample of X-ray clusters selected serendipitously from the ROSAT PSPC data archive. We spectroscopically confirm 15 clusters in the range 0.3 < z < 0.7, to a flux limit…

Astrophysics · Physics 2009-10-30 C. A. Collins , D. J. Burke , A. K. Romer , R. M. Sharples , R. C. Nichol

We perform simulations of star cluster formation to investigate the morphological evolution of embedded star clusters in the earliest stages of their evolution. We conduct our simulations with Torch, which uses the AMUSE framework to couple…

The mass fraction of hot gas in clusters is a basic quantity whose level and dependence on the cluster mass and redshift are intimately linked to all cluster X-ray and SZ measures. Modeling the evolution of the gas fraction is clearly a…

Astrophysics of Galaxies · Physics 2015-06-22 Irina Dvorkin , Yoel Rephaeli

We evaluate the dependence of the cluster correlation length r_c on the mean intercluster separation D_c, for three models with critical matter density, vanishing vacuum energy (Lambda = 0) and COBE normalized: a tilted CDM (tCDM) model…

Astrophysics · Physics 2009-10-31 A. Gardini , S. A. Bonometto , G. Murante , G. Yepes

We study the evolution of the ICM with a sample of 70 galaxy clusters spanning 0.18 < z < 1.24. We find that X-ray luminosity and ICM mass at a fixed temperature evolve with redshift in a manner inconsistent with the standard self-similar…

Astrophysics · Physics 2007-11-01 T. B. O'Hara , J. J. Mohr , A. J. R. Sanderson

(Abridged) We analyze photometry and spectroscopy of a sample of 63 clusters at 0.3<z<0.9 drawn from the Las Campanas Distant Cluster Survey to empirically constrain models of cluster galaxy evolution. Specifically, by combining data on our…

Astrophysics · Physics 2009-11-07 Amy E. Nelson , Anthony H. Gonzalez , Dennis Zaritsky , Julianne J. Dalcanton

We use hydrodynamical simulations of different dark energy cosmologies to investigate the concentration-mass (c-M) relation in galaxy clusters. In particular, we consider a reference \Lambda CDM model, two quintessence models with inverse…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-05 Cristiano De Boni , Stefano Ettori , Klaus Dolag , Lauro Moscardini

We quantify the morphologies and dynamical states of 59 galaxy clusters using the power-ratio technique of Buote & Tsai applied to ROSAT PSPC X-ray images. The clusters exhibit a particularly strong $P_2/P_0 - P_4/P_0$ correlation in the…

Astrophysics · Physics 2009-10-28 David A. Buote , John C. Tsai

Understanding the evolution of scaling relations between the observable properties of clusters and their total mass is key to realizing their potential as cosmological probes. In this study, we investigate whether the evolution of cluster…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-16 Benedikt Diemer , Andrey V. Kravtsov , Surhud More

We investigate the dependence of cluster abundance $n(>M,r_{cl})$, i.e., the number density of clusters with mass larger than $M$ within radius $r_{cl}$, on scale parameter $r_{cl}$. Using numerical simulations of clusters in the CDM…

Astrophysics · Physics 2009-10-30 Wen Xu , Li-Zhi Fang , Xiang-Ping Wu

We investigate the growth over time of 20 massive (> 3 keV) clusters in a hydrodynamical simulation of the LambdaCDM cosmology with radiative cooling. The clusters show a variety of formation histories: some accrete most of their mass in…

Astrophysics · Physics 2009-11-10 David R. Rowley , Peter A. Thomas , Scott T. Kay

We measure the morphology--density relation (MDR) and morphology-radius relation (MRR) for galaxies in seven z ~ 1 clusters that have been observed with the Advanced Camera for Surveys on board the Hubble Space Telescope. Simulations and…

We use a representative sample of 65 galaxy clusters observed with the Einstein IPC to constrain the range of cluster X-ray morphologies. We develop and apply quantitative and reproducible measures to constrain the intrinsic distributions…

Astrophysics · Physics 2016-08-30 J. J. Mohr , A. E. Evrard , D. G. Fabricant , M. J. Geller

Clustering is widely used in unsupervised learning to find homogeneous groups of observations within a dataset. However, clustering mixed-type data remains a challenge, as few existing approaches are suited for this task. This study…

Machine Learning · Statistics 2025-11-26 Badih Ghattas , Alvaro Sanchez San-Benito

We study the cluster mass function in mixed dark matter (MDM) models, using two COBE normalized simulations with Omega_h = 0.26 and n=1.2, and Omega_h = 0.14 and n = 1.05, both with 2 massive nu's (MDM1 and MDM2, respectively). For the sake…

Astrophysics · Physics 2009-10-31 A. Gardini , S. A. Bonometto , G. Murante