Related papers: The Alignment of Clusters using Large Scale Simula…
Using a sample of $>200$ clusters, each with typically $100-200$ spectroscopically confirmed cluster members, we search for a signal of alignment between the Position Angle (PA) of the Brightest Cluster Galaxy (BCG) and the distribution of…
We investigate the effects of a coupled Dark Energy (cDE) scalar field on the alignment between satellites and matter distributions in galaxy clusters. Using high-resolution N-body simulations for LCDM and cDE cosmological models, we…
The latest cosmological observables analyses seem to converge to a concordant view of the cosmological model: namely the power law Lambda-CDM. The recent WMAP results comfort this new standard model. Nevertheless, some degeneracy in the CMB…
[Abridged] We use mock catalogues based on the GALICS model (Hatton et al. 03) to explore the nature of galaxy clustering observed in the SDSS. We measure low and high order angular clustering statistic from these mock catalogues, after…
Galaxy clusters are connected at their peripheries to the large scale structures by cosmic filaments that funnel accreting material. These filamentary structures are studied to investigate both environment-driven galaxy evolution and…
We study the luminosity gap, dm12, between the first and second ranked galaxies in a sample of 59 massive galaxy clusters, using data from the Hale Telescope, HST, Chandra, and Spitzer. We find that the dm12 distribution, p(dm12), is a…
Using a large N-body cosmological simulation combined with a subgrid treatment of galaxy formation, we study the formation and evolution of the galaxy and cluster population in a comoving volume (100 Mpc)^3 in a LCDM universe. At z = 0, our…
Galaxy bias, the unknown relationship between the clustering of galaxies and the underlying dark matter density field is a major hurdle for cosmological inference from large-scale structure. While traditional analyses focus on the absolute…
I review recent progress in understanding and modeling galaxy clustering in cosmological simulations, with emphasis on models based on high-resolution dissipationless simulations. During the last decade, significant advances in our…
The position angles of a large number of Abell and Shectman clusters (in total 637 clusters), identified in the Lick map as surface density enhancements, are estimated. Using published redshifts for 277 of these I have detected strong…
Modified gravity and massive neutrino cosmologies are two of the most interesting scenarios that have been recently explored to account for possible observational deviations from the concordance $\Lambda$-cold dark matter ($\Lambda$CDM)…
We report a promising candidate for a distant supercluster at z $\sim 1.1$ in the Dark Energy Survey Science Verification data. We examine smoothed semi-3D galaxy density maps in various photo-z slices. Among several overdense regions, in…
The alignment between brightest cluster galaxies (BCGs) and host clusters can reveal the mystery of formation and evolution for galaxy clusters. We measure cluster orientations in optical based on the projected distribution of member…
We examine the alignment between Brightest Cluster Galaxies (BCGs) and their host clusters in a sample of 7031 clusters with 0.08<z<0.44 found using a matched-filter algorithm and an independent sample of 5744 clusters with 0.1<z<0.3…
We use two high resolution CDM simulations to show that (i) when clusters of galaxies form the infall pattern of matter is not random but shows clear features which are correlated in time; (ii) in addition, the infall patterns are…
Clusters of galaxies are merging during the formation of large-scale structures in the Universe. Based on optical survey data, we identify a large sample of pre-mergers of galaxy clusters and merging subclusters in rich clusters. We find…
We combine 10 high resolution resimulations of cluster--sized dark haloes with semi--analytic galaxy formation modelling in order to compare the number density and velocity dispersion profiles of cluster galaxies with those of dark matter…
We use numerical simulations of different dark energy cosmologies to investigate the concentration-mass (c-M) relation in galaxy clusters. In particular, we consider a reference Lambda cold dark matter (LambdaCDM) model, two models with…
Recent observations in galaxies and clusters indicate dark matter density profiles exhibit core-like structures which contradict to the numerical simulation results of collisionless cold dark matter. The idea of self-interacting cold dark…
Various cosmological applications of galaxy clusters are presented. Clusters are used to determine the baryon fraction, dark matter distribution and the matter density of the universe. They also contain a wealth of information about…