Related papers: Voids and Superstructures: correlations and induce…
Galaxy evolution is in transition from an early universe dominated by hierarchical clustering to a future dominated by secular processes. These result from interactions involving collective phenomena such as bars, oval disks, spiral…
We extend earlier work on the problem of estimating the void-volume function -- the abundance and evolution of large voids which grow gravitationally in an expanding universe -- in two ways. The first removes an ambiguity about how the…
Mass segregation, a tendency of more massive galaxies being distributed closer to the cluster center, is naturally expected from dynamical friction, but its presence is still controversial. Using deep optical observations of 14 Abell…
The properties of galaxies depend on their environment: red, passive elliptical galaxies are usually located in denser environments than blue, star-forming spiral galaxies. This difference in galaxy populations can be detected at all scales…
Galaxies congregate in clusters and along filaments, and are missing from large regions referred to as voids. These structures are seen in maps derived from spectroscopic surveys that reveal networks of structure that are interconnected…
Galaxy groups are more than an intermediate scale between clusters and halos hosting individual galaxies, they are crucial laboratories capable of testing a range of astrophysics from how galaxies form and evolve to large scale structure…
The symmetron field has an environment (density) dependent behavior which is a common feature of the models with the screening mechanism and results in a rich phenomenology. This model can produce domain walls between regions with different…
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…
The formation of astrophysical structures, such as stars, compact objects but also galaxies, entail an,enhancement of densities by many orders of magnitude which occurs through gravitational collapse. The role played by turbulence during…
We follow the evolution of galaxy systems in numerical simulation. Our goal is to understand the role of density perturbations of various scales in the formation and evolution of the cosmic web. We perform numerical simulations with the…
[ABRIDGED] Galaxy evolution is shaped by internal and external mechanisms that regulate the baryon cycle and star formation activity. We present a theoretical framework based on the GAlaxy Evolution and Assembly (GAEA) semi-analytic model.…
The intrinsic alignments of galaxies, i.e., the correlation between galaxy shapes and their environment, are a major source of contamination for weak gravitational lensing surveys. Most studies of intrinsic alignments have so far focused on…
As an alternative way of describing the cosmological velocity field, we discuss the evolution of rotational invariants constructed from the velocity gradient tensor. Compared with the traditional divergence-vorticity decomposition, these…
We present an analytic model for the sizes of voids in the galaxy distribution. Peebles and others have recently emphasized the possibility that the observed characteristics of voids may point to a problem in galaxy formation models, but…
Galaxy clusters are currently the endpoint of the hierarchical structure formation; they form via the accretion of dark matter and cosmic gas from their local environment. In particular, filaments contribute grandly by accreting gas from…
We review the structural properties of giant extragalactic HII regions and HII galaxies based on 2D hydrodynamic calculations, and propose an evolutionary sequence that accounts for their observed detailed structure. The model assumes a…
We study how the properties of cosmic voids depend on those of the tracer galaxy populations in which they are identified. We use a suite of halo occupation distribution (HOD) mocks in a simulation, identify voids in these populations using…
We give a summary of our recent studies of spatial and velocity biases of galaxy-size halos in cosmological models. Recent progress in numerical techniques made it possible to simulate halos in large volumes with a such accuracy that halos…
The evolution of marginally bound supercluster-like objects in an accelerating LambdaCDM Universe is followed, by means of cosmological simulations, from the present time to an expansion factor a = 100. The objects are identified on the…
The logarithmic superfluid theory of physical vacuum predicts that gravity is an induced phenomenon, which has a multiple-scale structure. At astronomical scales, as the distance from a gravitating center increases, gravitational potential…