We present the results from the dynamical analysis of the cluster of galaxies RX J0152.7−1357, which shows a complex structure in its X–ray emission, with two major clumps in the central region, and a third clump in the Eastern region. Our analysis is based on redshift data for 187 galaxies. We find that RX J0152.7−1357 appears as a well isolated peak in the redshift space at z = 0.836, which i...

We obtained precise line-of-sight radial velocities of 23 member stars of the remote halo globular cluster Palomar 4 (Pal 4) using the High Resolution Echelle Spectrograph at the Keck I telescope. We also measured the mass function of the cluster down to a limiting magnitude of V ∼ 28 mag using archival Hubble Space Telescope/Wide Field Planetary Camera 2 (WFPC2) imaging. We derived the cluster...

The Galactic open cluster Westerlund 1 was found only a few years ago to be much more massive than previously thought, with evidence suggesting its mass to be in excess of ∼10 5 M ⊙ , in the range spanned by young extragalactic star clusters. Unlike those clusters its proximity makes spatially resolved studies of its stellar population feasible. It is therefore the ultimate template for a young...

The dynamics and energy conversion and redistribution pathways in collisions of nanocrystals with bare solid surfaces and with adsorbed liquid films are investigated with molecular dynamics simulations. While impact of an ordered Cu14, icosahedral cluster on a bare C u ( l l 1 ) surface at velocities larger than thermal leads to various outcomes including implantation, indentation, disordering,...

We show that by directly correlating the cluster kinetic Sunyaev Zeldovich (KSZ) flux, the cluster peculiar velocity power spectrum can be measured to ∼ 10% accuracy by future large sky coverage KSZ surveys. This method is almost free of systemics entangled in the usual velocity inversion method. The direct correlation brings extra information of density and velocity clustering. We utilize thes...

We simulate the dynamics of fractal star clusters, in order to investigate the evolution of substructure in recently formed clusters. The velocity dispersion is found to be the key parameter determining the survival of substructure. In clusters with a low initial velocity dispersion, the ensuing collapse of the cluster tends to erase substructure, although some substructure may persist beyond t...

Recent observations of white dwarfs in globular clusters indicate that these stars may get a velocity kick during their time as giants. This velocity kick could originate naturally if the mass loss while on the asymptotic giant branch is slightly asymmetric. The kicks may be large enough to dramatically change the radial distribution of young white dwarfs, giving them larger energies than other...

Aims. To conduct an intensive study of the rich, X-ray luminous galaxy cluster Abell 773 at z = 0.22 containing a diffuse radio halo to determine its dynamical status. Methods. Our analysis is based on new spectroscopic data obtained at the TNG telescope for 107 galaxies, 37 spectra recovered from the CFHT archive and new photometric data obtained at the Isaac Newton Telescope. We use statistic...

We present a photometric and spectroscopic study of stellar populations in the X-ray-luminous cluster of galaxies RXJ0142.0+2131 at z = 0.280. This paper analyses the results of high signal-to-noise spectroscopy, as well as g-, r-, and i-band imaging, using the Gemini Multi-Object Spectrograph on Gemini North. Of 43 spectroscopic targets, we find 30 cluster members over a range in color. Centra...

We study the motion of stars in a star cluster which revolves in a circular orbit about its parent galaxy. The star cluster is modelled as an ellipsoid of uniform spatial density. We exhibit two 2-parameter families of self-consistent equilibrium models in which the velocity at each point is confined to a line in velocity space. We exhibit the link between this problem and that of a uniform rot...