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The projected gravitational potential of galaxy clusters is reflected in both their X-ray emission and their imprint on the images of background sources due to their gravitational lensing effects. Since these projections of the potential…

天体物理学 · 物理学 2007-05-23 Matthias Bartelmann , Tsafrir S. Kolatt

It is shown in this paper that deviations of galaxy cluster lenses from spherical symmetry can render mass estimates for galaxy clusters based on the formation of large arcs systematically to high. Numerical models show that the mass needed…

天体物理学 · 物理学 2011-05-23 Matthias Bartelmann

The number density of galaxy clusters as a function of mass and redshift is a sensitive function of the cosmological parameters. To use clusters for cosmological parameter studies, it is necessary to determine their masses as accurately as…

宇宙学与河外天体物理 · 物理学 2023-07-19 J. ZuHone , Y. E. Bahar , V. Biffi , K. Dolag , J. Sanders , E. Bulbul , T. Liu , T. Dauser , O. König , X. Zhang , V. Ghirardini

We present measurements of the masses of 20 X-ray luminous clusters of galaxies at intermediate redshifts, determined from a weak lensing analysis of deep archival R-band data obtained using the Canada-France-Hawaii-Telescope. Compared to…

天体物理学 · 物理学 2009-06-23 Henk Hoekstra

A synopsis of the recent results from our study of galaxy-galaxy lensing in clusters is presented. We have applied our analysis techniques to the sample of HST cluster-lenses that span a redshift range from redshift 0.18 to 0.58. We find…

天体物理学 · 物理学 2007-05-23 Priyamvada Natarajan , Jean-Paul Kneib , Ian Smail

We present an investigation of the effects of asphericity on the estimates of total mass and gas mass fraction in galaxy clusters from X-ray observations. We model the aspherical shape of galaxy clusters by a triaxial model and compare the…

天体物理学 · 物理学 2009-11-07 Rocco Piffaretti , Philippe Jetzer , Sabine Schindler

We assess a claim that observed galaxy clusters with mass ~10^14 Msun are more centrally concentrated than predicted in LCDM. We generate mock strong gravitational lensing observations, taking the lenses from a cosmological hydrodynamical…

宇宙学与河外天体物理 · 物理学 2020-06-02 Andrew Robertson , Richard Massey , Vincent Eke

All estimates of cluster mass have some intrinsic scatter and perhaps some bias with true mass even in the absence of measurement errors for example caused by cluster triaxiality and large scale structure. Knowledge of the bias and scatter…

宇宙学与河外天体物理 · 物理学 2017-10-04 S. Andreon , G. Trinchieri , A. Moretti , J. Wang

Using the brightest clusters in the ROSAT All-Sky Survey we compiled an X-ray flux-limited sample of galaxy clusters. The clusters have been reanalysed using ROSAT PSPC pointed observations if possible. The gravitational mass has been…

天体物理学 · 物理学 2007-05-23 Thomas H. Reiprich , Hans Boehringer

The knowledge of the redshift of multiple images in cluster-lenses allows to determine precisely the total projected mass within the Einstein radius. The observation of various multiple images in a same cluster is opening new possibilities…

天体物理学 · 物理学 2007-05-23 G. Golse , J. -P. Kneib , G. Soucail

Machine learning (ML) techniques, in particular supervised regression algorithms, are a promising new way to use multiple observables to predict a cluster's mass or other key features. To investigate this approach we use the \textsc{MACSIS}…

宇宙学与河外天体物理 · 物理学 2019-01-16 Thomas J. Armitage , Scott T. Kay , David J. Barnes

Previous comparisons of optical and X-ray observations of clusters of galaxies have lead to the so-called ``$\beta$ - discrepancy'' that has persisted for the last decade. The standard hydrostatic-isothermal model for clusters predicts that…

天体物理学 · 物理学 2009-10-22 Neta A. Bahcall , Lori M. Lubin

When measuring the observed pressure, density or temperature profiles of the intracluster gas, and hence the mass of clusters of galaxies, projection effects or departures from the spherical symmetry hypothesis may induce biases. In order…

宇宙学与河外天体物理 · 物理学 2024-03-08 Théo Lebeau , Jenny G. Sorce , Nabila Aghanim , Elena Hernández-Martínez , Klaus Dolag

A tight mass-temperature relation, M(r)/r ~ T_X, is expected in most cosmological models if clusters of galaxies are homologous and the intracluster gas is in global equilibrium with the dark matter. We here calibrate this relation using 8…

天体物理学 · 物理学 2009-10-30 Jens Hjorth , Jamila Oukbir , Eelco van Kampen

The X-ray regime, where the most massive visible component of galaxy clusters, the intra cluster medium (ICM), is visible, offers directly measured quantities, like the luminosity, and derived quantities, like the total mass, to…

宇宙学与河外天体物理 · 物理学 2017-06-28 G. Schellenberger , T. H. Reiprich

We present the first measurement of the mass function of galaxy clusters based directly on cluster masses derived from observations of weak gravitational lensing. To investigate the degree of sample incompleteness resulting from the X-ray…

天体物理学 · 物理学 2009-02-06 H. Dahle

The X-ray cluster gas density distribution in hydrostatic equilibrium is computed from the universal density profile of the dark matter halo recently proposed by Navarro, Frenk and White (1996, 1997). If one assumes the isothermality, the…

天体物理学 · 物理学 2009-10-30 Nobuyoshi Makino , Shin Sasaki , Yasushi Suto

The application to observational data of the generalized scaling relations (gSR) presented in Ettori et al. (2012) is here discussed. We extend further the formalism of the gSR in the self-similar model for X-ray galaxy clusters, showing…

宇宙学与河外天体物理 · 物理学 2015-06-16 S. Ettori

The main goal of this work is to compare the results of three dynamical mass estimators to the X-ray hydrostatic values, focussing on massive galaxy clusters at intermediate redshifts $z\sim0.3$. We estimated dynamical masses with the…

宇宙学与河外天体物理 · 物理学 2017-10-25 G. Foëx , H. Böhringer , G. Chon