Related papers: Small Deviations from Gaussianity and The Galaxy C…
We study statistical properties of galaxy structures in several samples extracted from the 2dF Galaxy Redshift Survey. In particular, we measured conditional fluctuations by means of the scale-length method and determined their probability…
We discuss correlation properties of a general mass density field introducing a classification of structures based on their complexity. Standard cosmological models for primordial mass fluctuations are characterized by a sort of large-scale…
We discuss the non--linear growth of the kurtosis of the smoothed peculiar velocity field (along an arbitrary direction), in an Einstein--de Sitter universe, induced by Gaussian primordial density fluctuations. Applying the perturbative…
In the current paradigm there is a non-trivial bias expected in the process of galaxy formation. Thus, the observed statistical properties of the galaxy distribution do not necessarily extend to the underlying matter distribution.…
In order to assess whether the environment has a significant effect on galaxy sizes, we compare the mass--size relations of cluster and field galaxies in the $0.4 < z < 0.8$ redshift range from the ESO Distant Cluster Survey (EDisCS) using…
We investigate the evolution of the skewness of the distribution of density fluctuations in CDM models with both Gaussian and non--Gaussian initial fluctuations. We show that the method proposed by Coles \& Frenk (1991), which uses the…
A new and powerful probe of the origin and evolution of structures in the Universe has emerged and been actively developed over the last decade. In the coming decade, non-Gaussianity, i.e., the study of non-Gaussian contributions to the…
We investigated the evolution of clusters of galaxies using self-consistent N-body simulations. We varied the initial model of galaxies and clusters, and studied the dependence of evolution on initial conditions. We found that the growth…
Clusters of galaxies are the largest gravitationally bound systems and therefore provide an important way of studying the formation and evolution of the large scale structure of the Universe. Cluster evolution can be inferred from…
We investigated the evolution of clusters of galaxies using self-consistent $N$-body simulations in which each galaxy was modeled by many particles. We carried out simulations for about 20 cases using different initial conditions. In all…
The combination of measurements of the local abundance of rich clusters of galaxies and its evolution to higher redshift offers the possibility of a direct measurement of $\Omega_0$ with little contribution from other cosmological…
Globular clusters (GCs) constitute a system which is evolving because of various interactions with the galactic environment. Evolution may be the explanation of many observed features of Globular Cluster Systems (GCSs); the different radial…
We discuss two slightly counter-intuitive findings about the environmental dependence of clustering in the Sloan Digital Sky Survey. First, we find that the relation between clustering strength and density is not monotonic: galaxies in the…
We discuss the diffuse emission of gamma rays and neutrinos from galaxy clusters in the viable models for structure formation in the universe. We use a self-consistent picture for cluster formation and evolution starting from a primordial…
The properties of galaxies are strongly correlated with their environment, with red galaxies dominating galaxy clusters and blue galaxies dominating the general field. However, not all field galaxies are young: studies of the colors, line…
The large-scale structure of the Universe is thought to evolve by a process of gravitational amplification from low-amplitude Gaussian noise generated in the early Universe. The later, non-linear stages of gravitation-induced clustering…
With the advent of galaxy surveys which provide large samples of galaxies or galaxy clusters over a volume comparable to the horizon size (SDSS-III, HETDEX, Euclid, JDEM, LSST, Pan-STARRS, CIP etc.) or mass-selected large cluster samples…
This paper reviews the measurements of galaxy correlations at high redshifts, and discusses how these may be understood in models of hierarchical gravitational collapse. The clustering of galaxies at redshift one is much weaker than at…
The K-band Hubble diagram of Brightest Cluster Galaxies (BCGs) is presented for a large, X-ray selected cluster sample extending out to z = 0.8. The controversy over the degree of BCG evolution is shown to be due to sample selection, since…
We point out that a light scalar field fluctuating around a symmetry-enhaced point can generate large non-Gaussianity in density fluctuations. We name such a particle as an "ungaussiton", a scalar field dominantly produced by the quantum…