نتایج جستجو برای: cluster of galaxy

تعداد نتایج: 21184710  

2007
RAVI K. SHETH WILLIAM C. SASLAW

We develop a technique, based on the galaxy distribution function, to synthesize the observed distribution of galaxies. It populates space with a Poisson distribution of cluster centers and places particles around each center according to a speciic prescription. We specify each cluster, assumed to be spherical, by three quantities: the number of particles in the cluster, its radius, and its rad...

1996
Mark Dickinson

High redshift galaxy clusters have traditionally been a fruitful place to study galaxy evolution. I review various search strategies for finding clusters at z > 1. Most efforts to date have concentrated on the environments of distant AGN. I illustrate these with data on the cluster around 3C 324 (z = 1.2) and other, more distant systems, and discuss possibilities for future surveys with large t...

1999
L. R. Jones T. J. Ponman Duncan A. Forbes

The group of galaxies RXJ1340.6+4018 has approximately the same bolometric X-ray luminosity as other bright galaxy groups and poor clusters such as the Virgo cluster. However, 70% of the optical luminosity of the group comes from a dominant giant elliptical galaxy, compared to 5% from M87 in Virgo. The second brightest galaxy in RXJ1340.6+4018 is a factor of 10 fainter (∆m12=2.5 mag) than the d...

2008
M. J. Pereira

We investigate the role of parametric tidal interactions between cluster galaxies and the cluster potential by considering galaxy and cluster dynamical properties and drawing an analogy between these systems and the Milky Way-dSph system. We suggest that some cluster galaxies are indeed undergoing resonant excitation and argue that this will cause a tendency for alignment of the galaxies’ long ...

2006
S. Schindler

The enrichment of the Intra-Cluster Medium (ICM) with heavy elements is reviewed. There is now good observational evidence for enrichment including abundance ratios and metallicity distributions. Various processes involved in the enrichment process – rampressure stripping, galactic winds, galaxy-galaxy interactions, AGN outflows and intra-cluster supernovae – are described. Simulations of the I...

2000
V. N. Lukash

We propose a Λ-inflation model which explains a significant part of the COBE signal by primordial cosmic gravitational waves. The primordial density perturbations fulfill both the constraints of large-scale microwave background and galaxy cluster normalization. The model is tested against the galaxy cluster power spectrum and the high-multipole angular CMB anisotropy.

2008
Xiang-Ping Wu Zonghong Zhu

The associations of the angular positions of background quasars with foreground galaxies, clusters of galaxies and quasars are often attributed to the statistical lensing by gravitational potentials of the matter along the lines of sight, although it has been known that none of the individual objects (galaxies, clusters or quasars) are able to fully explain the reported amplitudes of the quasar...

2011
K. Andersson G. Bazin T. de Haan J. Ruel P. A. R. Ade K. A. Aird R. J. Foley R. Armstrong M. L. N. Ashby M. Bautz B. A. Benson L. E. Bleem M. Bonamente M. Brodwin J. E. Carlstrom C. L. Chang A. Clocchiatti T. M. Crawford A. T. Crites S. Desai M. A. Dobbs J. P. Dudley G. G. Fazio W. R. Forman G. Garmire E. M. George M. D. Gladders A. H. Gonzalez N. W. Halverson F. W. High G. P. Holder W. L. Holzapfel S. Hoover J. D. Hrubes C. Jones M. Joy R. Keisler L. Knox A. T. Lee E. M. Leitch M. Lueker D. Luong-Van D. P. Marrone J. J. McMahon J. Mehl S. S. Meyer J. J. Mohr T. E. Montroy S. S. Murray S. Padin T. Plagge C. Pryke C. L. Reichardt A. Rest J. E. Ruhl B. R. Saliwanchik A. Saro K. K. Schaffer L. Shaw E. Shirokoff J. Song H. G. Spieler B. Stalder S. A. Stanford Z. Staniszewski A. A. Stark K. Story C. W. Stubbs K. Vanderlinde J. D. Vieira A. Vikhlinin R. Williamson A. Zenteno

Using the South Pole Telescope (SPT), we have discovered the most massive known galaxy cluster at z > 1, SPT-CL J2106-5844. In addition to producing a strong Sunyaev–Zel’dovich (SZ) effect signal, this system is a luminous X-ray source and its numerous constituent galaxies display spatial and color clustering, all indicating the presence of a massive galaxy cluster. Very Large Telescope and Mag...

2008
Omar López-Cruz

We present a study of the luminosity and color properties of galaxies selected from a sample of 57 low-redshift Abell clusters. We utilize the non-parametric dwarf-to-giant ratio (DGR) and the blue galaxy fraction (fb) to investigate the clustercentric radial-dependent changes in the cluster galaxy population. Composite cluster samples are combined by scaling the counting radius by r200 to mini...

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