We present results from two high–resolution hydrodynamical simulations of proto–cluster regions at z ≃ 2.1. The simulations have been compared to observational results for the socalled Spiderweb galaxy system, the core of a putative proto–cluster region at z = 2.16, found around a radio galaxy. The simulated regions have been chosen so as to form a poor cluster with M200 ≃ 10 hM⊙ (C1) and a ric...

Various cosmological applications of galaxy clusters are presented. Clusters are used to determine the baryon fraction, dark matter distribution and the matter density Ωm of the universe. They also contain a wealth of information about structure formation and evolution on different scales: large-scale structure, cluster formation and also galaxy formation via the interaction of cluster galaxies...

it is inferred from the symmetrical and luminous x-ray emission of fossil groups that they are mature, relaxed galaxy systems. cosmological simulations and observations focusing on their dark halo and inter-galactic medium properties confirm their early formation. recent photometric observations suggest that, unlike the majority of non-fossil brightest group galaxies (bggs), the central early-t...

Gravitational lensing is an important tool for probing the mass distribution of galaxies. In this letter we report the discovery of a new quadruple lens HST 1411+5211 found in archived WFPC2 images of the galaxy cluster CL140933+5226. If the galaxy is a cluster member then its redshift is z = 0.46. The images of the source appear unresolved in the WFC implying that the source is a quasar. We ha...

New globular clusters may form in the merger of two galaxies. Perhaps the best examples of merger remnants are the set of ellipticals with kinematically–distinct cores. Here we present HST WFPC2 imaging of 14 kinematically–distinct core ellipticals to examine their globular cluster systems. In particular, we probe the galaxy central regions, for which we might expect to see the strongest signat...

We present a five-band Herschel study (100–500 μm) of three galaxy clusters at z 1.2 ~ from the Spitzer Adaptation of the Red-Sequence Cluster Survey. With a sample of 120 spectroscopically confirmed cluster members, we investigate the role of environment on galaxy properties utilizing the projected cluster phase space (line-of-sight velocity versus clustercentric radius), which probes the time...

In this paper we present the main concepts behind the Galaxy cluster management framework. Galaxy is focused on servicing large-scale enterprise clusters through the use of novel, highly scalable communication and management techniques. Galaxy is a flexible framework built upon the notion of low-level management of cluster farms, where within these farms islands of specific cluster management t...