Results 21 to 30 of about 66,428 (293)
Dark Matter in Groups and Clusters of Galaxies [PDF]
AbstractWe compare the characteristics of stellar populations with those of dark halos. Dark matter around galaxies, and in groups, clusters and voids is discussed. Modern data suggest that the overall density of matter in the Universe is ΩM = 0.3 ± 0.1, about 80 % of this matter is nonbaryonic dark matter, and about 20 % is baryonic, mostly in the ...
J. Einasto, M. Einasto
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The colours of satellite galaxies in groups and clusters [PDF]
Current models of galaxy formation predict satellite galaxies in groups and clusters that are redder than observed. We investigate the effect on the colours of satellite galaxies produced by the ram pressure stripping of their hot gaseous atmospheres as the satellites orbit within their parent halo. We incorporate a model of the stripping process based
Andreea S. Font+8 more
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Accretion of galaxy groups into galaxy clusters [PDF]
ABSTRACT We study the role of group infall in the assembly and dynamics of galaxy clusters in ΛCDM. We select 10 clusters with virial mass M200 ∼ 1014 $\rm M_\odot$ from the cosmological hydrodynamical simulation Illustris and follow their galaxies with stellar mass M⋆ ≥ 1.5 × 108 $\rm M_\odot$.
Laura V. Sales+3 more
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INDIVIDUAL AND GROUP GALAXIES IN CNOC1 CLUSTERS [PDF]
ApJ ...
I. H. Li, H. K. C. Yee, E. Ellingson
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Properties of Fossil Groups of Galaxies
We review the formation and evolution of fossil groups and clusters from both the theoretical and the observational points of view. In the optical band, these systems are dominated by the light of the central galaxy.
J. Alfonso L. Aguerri, Stefano Zarattini
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Galaxy and mass assembly (GAMA): the clustering of galaxy groups [PDF]
ABSTRACT We explore the clustering of galaxy groups in the Galaxy and Mass Assembly (GAMA) survey to investigate the dependence of group bias and profile on separation scale and group mass. Due to the inherent uncertainty in estimating the group selection function, and hence the group autocorrelation function, we instead measure the ...
S D Riggs+6 more
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The Effect of Splashback on Weak Lensing Mass Estimates of Galaxy Clusters and Groups
The splashback radius of a dark matter halo, which corresponds to the first apocenter radius reached by infalling matter and substructures, has been detected around galaxy clusters using a multitude of observational methods, including weak lensing ...
Yuanyuan Zhang+5 more
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ON THE BARYON FRACTIONS IN CLUSTERS AND GROUPS OF GALAXIES [PDF]
We present the baryon fractions of 2MASS groups and clusters as a function of cluster richness using total and gas masses measured from stacked ROSAT X-ray data and stellar masses estimated from the infrared galaxy catalogs. We detect X-ray emission even in the outskirts of clusters, beyond r_200 for richness classes with X-ray temperatures above 1 keV.
Xinyu Dai+3 more
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The accretion of galaxies into groups and clusters [PDF]
We use the galaxy stellar mass and halo merger tree information from the semi-analytic model galaxy catalogue of Font et al. (2009) to examine the accretion of galaxies into a large sample of groups and clusters, covering a wide range in halo mass (10E12.9 to 10E15.3 Msun/h), and selected from each of four redshift epochs (z=0, 0.5, 1.0 and 1.5).
Sean L. McGee+4 more
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Lost but not forgotten: Intracluster light in galaxy groups and clusters [PDF]
With Hubble Space Telescope imaging, we investigate the progenitor population and formation mechanisms of the intracluster light (ICL) for 23 galaxy groups and clusters ranging from 3$\times10^{13} 10^{11.6}$ M$_\odot$), while by 100 kpc this colour is ...
T. DeMaio+6 more
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