Related papers: Shapes and Probabilities of Galaxy Clusters
Clusters of galaxies, the most massive virialized systems known, provide a powerful tool for studying the structure, the mass density, and the cosmology of our universe. Clusters furnish one of the best estimates of the dynamical mass…
Combined HST, X-ray, and ground-based optical studies show that clusters of galaxies are largely "in place" by $z \sim 1$, an epoch when the Universe was less than half its present age. High resolution images show that elliptical, S0, and…
Groups and clusters of galaxies occupy a special position in the hierarchy of large-scale cosmic structures because they are the largest and the most massive (from ~10^13 Msun to over 10^15 Msun) objects in the universe that have had time…
The majority of bright distant quasars $(z {}^{>}_{\sim} 1)$ may form in massive mergers appearing in compact galaxy groups in/and young clusters. The expected tests are (i) large correlation signal for medium-$z$ QSOs $(1 < z < 2)$ and…
We explore galaxy properties and their link with environment and clustering using a population of ~1000 galaxies formed in a high resolution hydrodynamic simulation of the Lambda CDM cosmology. At the redshift we concentrate on, z=1, the…
Galaxy clusters are the largest structures in Universe. They are very important as both cosmological probes and astrophysical laboratories. Several methods have been developed to detect galaxy clusters with different techniques (optical,…
Hierarchical theories of structure formation predict that clusters of galaxies should be embedded in a web like structure, with filaments emanating from them to large distances. The amount of mass contained within such filaments near a…
We review progress in numerical simulations of star cluster formation. These simulations involve the bottom-up assembly of clusters through hierarchical mergers, which produces a fractal stellar distribution at young (~0.5 Myr) ages. The…
Except for crystalline or random structures, an agreed definition of complexity for intermediate and hence interesting cases does not exist. We fill this gap with a notion of complexity that characterises shapes formed by any finite number…
We study gravitational instabilities in disks, with special attention to the most massive clumps that form because they are expected to be the progenitors of globular-type clusters. The maximum unstable mass is set by rotation and depends…
Optical and X-ray studies have established the prevalence of significant substructure in clusters of galaxies, indicating that clusters are young systems, and that recent major mergers have occurred in many clusters. Numerical simulations…
Galaxy clusters approximate a planar (FP) distribution in a three-dimensional parameter space which can be characterized by optical luminosity, half-light radius, and X-ray luminosity. Using a high-quality catalog of cluster redshifts, we…
Clusters and groups of galaxies are highly aspherical, with shapes approximated by nearly prolate ellipsoids of revolution. An equally fundamental property is the shape of these objects in velocity space which is the anisotropy of the…
Most star complexes are in fact complexes of stars, clusters and gas clouds; term "star complexes" was introduced as general one disregarding the preferential content of a complex. Generally the high rate of star formation in a complex is…
Nearly a century after the true nature of galaxies as distant "island universes" was established, their origin and evolution remain great unsolved problems of modern astrophysics. One of the most promising ways to investigate galaxy…
Most formation scenarios of globular clusters assume a molecular cloud as the progenitor of the stellar system. However, it is still unclear, how this cloud is transformed into a star cluster, i.e. how the destructive processes related to…
With the help of a statistical parameter derived from optical spectra, we show that the current star formation rate of a galaxy, falling into a cluster along a supercluster filament, is likely to undergo a sudden enhancement before the…
Observations of the nearby large galaxies that can be examined in particularly close detail suggest that many have small stellar luminosity fractions in bulges and haloes. Simulations of galaxy formation tend to produce considerably larger…
The traditional method of morphological classification, by visual inspection of images of uniform quality and by reference to standards for each type, is critically examined. The rate of agreement among traditional morphologists on the…
In the most prominent current scenario of galaxy formation, galaxies form hierarchically through the merger of smaller systems. Such mergers could leave behind dynamical signatures which may linger long after the event. In particular, the…