There are few direct measurements of ICM velocity structure, despite its importance for understanding clusters. We present a detailed analysis the structure Centaurus cluster using XMM-Newton observations. Using new EPIC-pn energy scale calibration, which uses Cu Ka instrumental line as reference, we able to obtain with uncertainties down $\Delta v \sim 79$ km/s. create 2D spectral maps velocit...

We present new spectroscopic observations of the most distant X-ray selected galaxy cluster currently known, XMMXCS J2215.9−1738 at z = 1.457, obtained with the DEIMOS instrument at the W. M. Keck Observatory, and the FORS2 instrument on the ESO Very Large Telescope. Within the cluster virial radius, as estimated from the cluster X-ray properties, we increase the number of known spectroscopic c...

We present a statistical study of substructure within a sample of ΛCDM clusters and galaxies simulated with up to 25 million particles. With thousands of subhalos per object we can accurately measure their spatial clustering and velocity distribution functions and compare these with observational data. The substructure properties of galactic halos closely resembles those of galaxy clusters with...

Richness is a key defining characteristic of a galaxy cluster. We measure the optical richness of galaxy clusters from the CNOC1 cluster redshift survey using the galaxy-cluster center correlation amplitude Bgc. We show that the Bgc values measured using photometric catalogs are consistent with those derived from redshift catalogs, indicating that richness can be measured reliably from photomet...

We present new spectroscopic observations of the most distant X-ray-selected galaxy cluster currently known, XMMXCS J2215.9 1738 at z 1⁄4 1:457, obtained with the DEIMOS instrument at the W. M. Keck Observatory and the FORS2 instrument on the ESO Very Large Telescope. Within the cluster virial radius, as estimated from the cluster X-ray properties, we increase the number of known spectroscopic ...

S U M M A R Y We examine the relations between spatial symmetry properties of earthquake patterns along faults in California (CA) and local velocity structure images to test the hypothesis that ruptures on bimaterial faults have statistically preferred propagation directions. The analysis employs seismic catalogues for 25 fault zones in CA. We distinguish between clustered and homogeneous parts...

We study the influence of converging cooling flow bulk motions on the SunyaevZel’dovich (SZ) effect. To that purpose we derive a modified Kompaneets equation which takes into account the contribution of the accelerated electron media of the cooling flow inside the cluster frame. The additional term is different from the usual kinematic SZ-effect, which depends linearly on the velocity, whereas ...