Related papers: High-z massive clusters as a test for dynamical co…
We report the discovery of a compact supercluster structure at z=0.9. The structure comprises three optically-selected clusters, all of which are detected in X-rays and spectroscopically confirmed to lie at the same redshift. The Chandra…
We present new Chandra observations of a high redshift (z~1) galaxy cluster discovered in the Red-Sequence Cluster Survey (RCS): RCS043938-2904.7. X-ray luminosity measurements and mass estimates are consistent with L_X-T_X and M_delta-T_X…
Observation of even a single massive cluster, especially at high redshift, can falsify the standard cosmological framework consisting of a cosmological constant and cold dark matter (LCDM) with Gaussian initial conditions by exposing an…
We use Chandra observations of nine optically and X-ray selected clusters in five different structures at z ~ 0.7-1.1 from the Observations of Redshift Evolution in Large-Scale Environments (ORELSE) survey to study diffuse X-ray emission…
Identifying galaxy clustering at high redshift (i.e. z > 1) is essential to our understanding of the current cosmological model. However, at increasing redshift, clusters evolve considerably in star-formation activity and so are less likely…
To date, 14 high-redshift (z>1.0) galaxy clusters with mass measurements have been observed, spectroscopically confirmed and are reported in the literature. These objects should be exceedingly rare in the standard LCDM model. We…
We present results of a combined X-ray/optical analysis of the dynamics of the massive cluster MACS J0358.8-2955 (z=0.428) based on observations with the Chandra X-ray Observatory, the Hubble Space Telescope, and the Keck-I telescope on…
We constrain the physical nature of dark matter using the newly identified massive merging galaxy cluster MACSJ0025.4-1222. As was previously shown by the example of the Bullet Cluster (1E0657-56), such systems are ideal laboratories for…
We report the discovery of a massive, X-ray-luminous cluster of galaxies at z=1.393, the most distant X-ray-selected cluster found to date. XMMU J2235.3-2557 was serendipitously detected as an extended X-ray source in an archival XMM-Newton…
Finding a sample of the most massive clusters with redshifts $z>0.6$ can provide an interesting consistency check of the $\Lambda$ cold dark matter ($\Lambda$CDM) model. Here we present results from our search for clusters with $0.6\lesssim…
We present an analysis of a 50ks XMM observation of the merging galaxy cluster ClJ0152.7-1357 at z=0.83. In addition to the two main subclusters and an infalling group detected in an earlier Chandra observation of the system, XMM detects…
We present joint X-ray and optical observations of the high redshift (z~0.83) lensing cluster CLJ0152.7-1357 made with the Chandra X-ray Observatory and the Keck telescope. We confirm the existence of significant substructure at both X-ray…
We present a strong lensing analysis and reconstruct the mass distribution of SPT-CL J0356-5337, a galaxy cluster at redshift z = 1.034. Our model supersedes previous models by making use of new multi-band HST data and MUSE spectroscopy. We…
The recent weak lensing measurement of the dark matter mass of the high-redshift galaxy cluster XMMUJ2235.3-2557 of (8.5 +- 1.7) x 10^{14} Msun at z=1.4, indicates that, if the cluster is assumed to be the result of the collapse of dark…
High-redshift galaxy clusters allow us to examine galaxy formation in extreme environments. Here we compile data for 15 $z>1$ galaxy clusters to test the predictions from a state-of-the-art semi-analytical model of galaxy formation. The…
To demonstrate the feasibility of studying the epoch of massive galaxy cluster formation in a more systematic manner using current and future galaxy surveys, we report the discovery of a large sample of proto-cluster candidates in the 1.62…
(Abridged) Distant galaxy clusters provide important tests of the growth of large scale structure in addition to highlighting the process of galaxy evolution in a consistently defined environment at large look back time. We present a sample…
Next-generation large-scale structure spectroscopic surveys will probe cosmology at high redshifts $(2.3 < z < 3.5)$, relying on abundant galaxy tracers such as Ly$\alpha$ emitters (LAEs) and Lyman break galaxies (LBGs). Medium-band…
We report on the XMM-Newton (XMM) observation of RXJ1053.7+5735, one of the most distant X-ray selected clusters of galaxies, which also shows an unusual double-lobed X-ray morphology, indicative of a possible equal-mass cluster merger. The…
We present first results on the use of a colour space filter for detecting galaxy clusters at cosmological redshifts in the XMM Large Scale Structure Survey. All clusters studied, but one, are successfully colour--detected in spite of their…