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We analyze the internal velocity dispersions of a sample of 172 nearby galaxy clusters (z < 0.15), each of which has at least 30 available galaxy redshifts, and spans a large richness range. Cluster membership selection is based on…

天体物理学 · 物理学 2010-04-06 Dario Fadda , Marisa Girardi , Giuliano Giuricin , Fabio Mardirossian , Marino Mezzetti

Understanding turbulence within the Intracluster Medium (ICM) of galaxy clusters is pivotal for comprehending their evolution and dynamics. Employing 3D magnetohydrodynamic (MHD) simulations of galaxy cluster mergers, we examine the…

星系天体物理 · 物理学 2025-07-30 Yue Hu , Alex Lazarian , G. Brunetti , John A. ZuHone

Measurements of the surface brightness distribution and of the velocity dispersion profile have been so far used to infer the inner dynamics of globular clusters. We show that those observations do not trace back the dark matter potentially…

天体物理学 · 物理学 2007-05-23 Francois Roueff , Pierre Salati , Richard Taillet

The large-scale structure in the distribution of galaxies is thought to arise from the gravitational instability of small fluctuations in the initial density field of the universe. A key test of this hypothesis is that superclusters of…

We constrain the internal dynamics of a stack of 10 clusters from the GCLASS survey at 0.87<z<1.34. We determine the stack cluster mass profile M(r) using the MAMPOSSt algorithm of Mamon et al., the velocity anisotropy profile beta(r) from…

宇宙学与河外天体物理 · 物理学 2016-10-12 A. Biviano , R. F. J. van der Burg , A. Muzzin , B. Sartoris , G. Wilson , H. K. C. Yee

We report new constraints on the local escape speed of our Galaxy. Our analysis is based on a sample of high velocity stars from the RAVE survey and two previously published datasets. We use cosmological simulations of disk galaxy formation…

I investigate an analytical model of galaxy clusters based on the assumption that the intracluster medium plasma is polytropic and is in hydrostatic equilibrium. The Einasto profile is adopted as a model for the spatial-density distribution…

宇宙学与河外天体物理 · 物理学 2018-10-31 Mohammad S. Mirakhor

We quantify the expected observed statistical and systematic uncertainties of the escape velocity as a measure of the gravitational potential and total mass of galaxy clusters. We focus our attention on low redshift (z < 0.15) clusters,…

宇宙学与河外天体物理 · 物理学 2015-06-16 Daniel Gifford , Christopher J. Miller , Nicholas Kern

The study of the kinematics of galaxies within clusters or groups has the limitation that only one of the three velocity components and only two of the three spatial components of a galaxy position in six-dimensional phase space can…

天体物理学 · 物理学 2009-10-31 Boudewijn F. Roukema , Stanislaw Bajtlik

A kinematic method to access cosmic acceleration based exclusively on the Sunyaev-Zel'dovich effect (SZE) and X-ray surface brightness data from galaxy clusters is proposed. By using the SZE/X-ray data from 38 galaxy clusters [Bonament et…

宇宙学与河外天体物理 · 物理学 2009-05-19 J. A. S. Lima , R. F. L. Holanda , J. V. Cunha

We summarize the method of mass modelling of galaxy clusters based on reproducing the dispersion and kurtosis of the projected velocity distribution of galaxies. The models are parametrized within the framework of the NFW density profile,…

天体物理学 · 物理学 2007-12-17 Ewa L. Lokas , Radoslaw Wojtak , Gary A. Mamon , Stefan Gottloeber

We use a high resolution collisionless simulation of a Virgo--like cluster in a $\Lambda$CDM cosmology to determine the velocity and clustering properties of the diffuse stellar component in the intracluster region at the present epoch. The…

Data from 58 strong-lensing events surveyed by the Sloan Lens ACS Survey are used to estimate the projected galaxy mass inside their Einstein radii by two independent methods: stellar dynamics and strong gravitational lensing. We perform a…

宇宙学与河外天体物理 · 物理学 2011-02-02 Antonio C. C. Guimarães , Laerte Sodré

We study the acceleration of cosmic rays by collisionless structure formation shocks with ENZO grid simulations. Data from the FERMI satellite enable the use of galaxy clusters as a testbed for particle acceleration models. Based on…

星系天体物理 · 物理学 2016-03-23 F. Vazza , M. Brueggen , D. Wittor , C. Gheller , D. Eckert , M. Stubbe

The caustic technique uses galaxy redshifts alone to measure the escape velocity and mass profiles of galaxy clusters to clustrocentric distances well beyond the virial radius, where dynamical equilibrium does not necessarily hold. We…

宇宙学与河外天体物理 · 物理学 2015-05-20 Ana Laura Serra , Antonaldo Diaferio , Giuseppe Murante , Stefano Borgani

We provide the first direct lifting of the mass/anisotropy degeneracy for a cluster of galaxies, by jointly fitting the line of sight velocity dispersion and kurtosis profiles of the Coma cluster, assuming an NFW tracer density profile, a…

天体物理学 · 物理学 2007-05-23 Gary A. Mamon , Ewa L. Lokas , Teresa Sanchis

We use an unprecedented data-set of about 600 redshifts for cluster members, obtained as part of a VLT/VIMOS large programme, to constrain the mass profile of the z=0.44 cluster MACS J1206.2-0847 over the radial range 0-5 Mpc (0-2.5 virial…

We use N-body simulations to study the shape of mean cluster density and velocity profiles formed via gravitational instability. The dependence of the final structure on both cosmology and initial density field is examined, using a grid of…

天体物理学 · 物理学 2009-10-22 Mary M. Crone , August E. Evrard , Douglas O. Richstone

Velocity fields in the cosmic web are fundamental to structure formation but remain difficult to observe directly beyond the linear regime. Here we present observational evidence that galaxy filaments connecting pairs of galaxy clusters…

宇宙学与河外天体物理 · 物理学 2026-01-27 Ji Yao , Huanyuan Shan , Pengjie Zhang , Xiaohu Yang , Jiale Zhou , Jiaxin Han , Peng Wang

Some observations such as those presented in Walker et al. show that the observed entropy profiles of the intra-cluster medium (ICM) deviate from the power-law prediction of adiabatic simulations. This implies that non-gravitational…

宇宙学与河外天体物理 · 物理学 2021-02-17 Zhenghao Zhu , Haiguang Xu , Dan Hu , Chenxi Shan , Yongkai Zhu , Shida Fan , Yuanyuan Zhao , Liyi Gu , Xiang-Ping Wu