Related papers: Has the Universe a honeycomb structure?
We use numerical simulations to examine the substructure within galactic and cluster mass halos that form within a hierarchical universe. Clusters are easily reproduced with a steep mass spectrum of thousands of substructure clumps that…
Elliptical and S0 galaxies dominate the galaxy population in nearby rich clusters such as Coma. Studies of the evolution of the colors, M/L ratios, and line indices of early-type galaxies indicate that they have been a highly homogeneous,…
We identify a spectroscopic sequence of galaxies, analogous to the Hubble sequence of morphological types, based on the Automatic Spectroscopic K-means (ASK) classification. Considering galaxy spectra as multidimensional vectors, the…
We find clusters and superclusters of galaxies using the Data Release 1 of the Sloan Digital Sky Survey. Density fields with smoothing lengthst of 10 and 0.8 Mpc/h are calculated. We found that galaxies and clusters in a high-density…
We present new (B,I) photometry for the globular cluster systems in eight Brightest Cluster Galaxies (BCGs), obtained with the ACS/WFC camera on the Hubble Space Telescope. In the very rich cluster systems that reside within these giant…
We analyse the K-band Hubble diagram for a sample of brightest cluster galaxies (BCGs) in the redshift range 0<z<1. In good agreement with earlier studies, we confirm that the scatter in the absolute magnitudes of the galaxies is small (0.3…
We probe the evolution of globular clusters that could form in giant molecular clouds within high-redshift galaxies. Numerical simulations demonstrate that the large and dense enough gas clouds assemble naturally in current hierarchical…
Recent surveys of star forming regions have shown that most stars, and probably all massive stars, are born in dense stellar clusters. The mechanism by which a molecular cloud fragments to form several hundred to thousands of individual…
Recent high-resolution observations with the Hubble Space Telescope (HST) reveal that young star clusters of extraordinary luminosity and compactness ("super star clusters") are commonly found in starburst systems. Cluster formation appears…
We calculate the mean power spectrum of galaxies using published power spectra of galaxies and clusters of galaxies. The mean power spectrum has a relatively sharp maximum on scale 120 Mpc (for Hubble constant h=1), followed by an almost…
We use the L-GALAXIES semi-analytic model to investigate the evolution of Brightest Cluster Galaxies (BCGs) found in clusters at $\rm z \sim 0$. BCGs are typically located in the central region of galaxy clusters, near the bottom of the…
Galactic globular clusters are not simple stellar populations. And nothing is simple in their study, basically because we try to reconstruct chains of events that occurred at redshift z > 2-3 by observing these objects at z=0, after a…
Recent extensive, multi-color deep surveys of galaxies open a possibility to get observational estimation of sizes for the largest structures in the Universe. Photometric redshift accuracy (about 0.03(1+z)) allows directly study clustering…
We discuss the mechanism of cluster formation in hierarchically collapsing molecular clouds. Recent evidence, both observational and numerical, suggests that molecular clouds (MCs) may be undergoing global, hierarchical gravitational…
Majority of all galaxies reside in groups of less than 50 member galaxies. These groups are distributed in various large-scale environments from voids to superclusters. Evolution of galaxies is affected by the environment in which they…
Clusters of galaxies are the largest gravitationally bounded structures in the Universe dominated by dark matter. We review the observational appearance and physical models of plasma structures in clusters of galaxies. Bubbles of…
Data are presently available on the luminosities and half-light radii of 101 globular clusters associated with low-luminosity parent galaxies. The luminosity distribution of globulars embedded in dwarf galaxies having $M_{v} > -16$ is found…
The most successful cosmological models to date envision structure formation as a hierarchical process in which gravity is constantly drawing lumps of matter together to form increasingly larger structures. Clusters of galaxies currently…
Luminosity Functions have been obtained for very faint dwarf galaxies in the cores of four rich clusters of galaxies (Abell 2052, 2107, 2199 and 2666). It is found that the luminosity function of dwarf galaxies rises very steeply in these…
In this paper I present some recent and new results regarding the effects of the cluster environment on the star formation history of galaxies. Three main aspects are discussed: the differences in the stellar population ages of cluster…