相关论文: How unusual are the Shapley Supercluster and the S…
The largest and the deepest super-structure known today is the Shapley super-cluster. This is the sky area with the highest over-density of galaxy clusters and therefore also an ideal region to test the effects of a high density environment…
We consider constraints on the amplitude of mass fluctuations in the universe, sigma_8, derived from two simple observations: the present number density of clusters and the amplitude of their correlation function. Allowing for the…
We investigate the gas mass function of clusters of galaxies to measure the density fluctuation spectrum on cluster scales. The baryon abundance confined in rich clusters is computed from the gas mass function and compared with the mean…
We study the statistical properties of the gravitational field generated by galaxy distribution observed bythe Sloan Digital Sky Survey (DR7). We characterize the probability density function of gravitational force fluctuations and relate…
Several large structures, including the Sloan Great Wall, the Huge Large Quasar Group, and a large gamma-ray burst cluster referred to as the Hercules-Corona Borealis Great Wall, appear to exceed the maximum structural size predicted by…
Extreme value statistics, or extreme statistics for short, refers to the statistics that characterizes rare events of either unusually high or low intensity: climate disasters like floods following extremely intense rains are among the…
Large galaxy redshift surveys have long been used to constrain cosmological models and structure formation scenarios. In particular, the largest structures discovered observationally are thought to carry critical information on the…
We investigate the properties of clusters of galaxies in two cosmological models using N-body simulations and the Press-Schecter (PS) theory. In the first model, the initial power spectrum of density fluctuations is in the form P(k) \propto…
We present the Shapley Optical Survey, a photometric study covering a 2 deg^2 region of the Shapley Supercluster core at z ~ 0.05 in two bands (B and R). The galaxy sample is complete to B=22.5 (>M^*+6, N_{gal}=16588), and R=22.0 (>M^*+7,…
Superclusters are the largest massive structures in the cosmic web on tens to hundreds of megaparsecs (Mpc) scales. They are the largest assembly of galaxy clusters in the Universe. Apart from a few detailed studies of such structures,…
Superclusters are the largest relatively isolated systems in the cosmic web. Using the SDSS BOSS survey we search for the largest superclusters in the redshift range $0.43<z<0.71$. We generate a luminosity-density field smoothed over $8…
Superstring flux compactifications can stabilize all moduli while leading to an enormous number of vacua solutions, each leading to different $4-d$ laws of physics. While the string landscape provides at present the only plausible…
We present a new catalogue of distances and peculiar velocities (PVs) of $34,059$ early-type galaxies derived from Fundamental Plane (FP) measurements using data from the Sloan Digital Sky Survey (SDSS). This $7016\,\mathrm{deg}^{2}$…
Velocity and density field reconstructions of the volume of the universe within 0.05c derived from the Cosmicflows-3 catalog of galaxy distances has revealed the presence of a filamentary structure extending across ~ 0.11c. The structure,…
In this paper I consider the nonlinear evolution of a rare density fluctuation in a random density field with Gaussian fluctuations, and I rigorously show that it follows the spherical collapse dynamics applied to its mean initial profile.…
Early JWST observations have revealed the ubiquitous presence in the early Universe, up to z about 16, of extreme baryon concentrations, namely forming globular clusters, extremely dense galaxies that may or may not be UV bright, and…
We apply the scale-length method to several three dimensional samples of the Two degree Field Galaxy Redshift Survey. This method allows us to map in a quantitative and powerful way large scale structures in the distribution of galaxies…
We study the gravitational influence of very large scale structures, as traced by clusters of galaxies, on the Local Group [LG] motion and the large scale flows. We derive from the distribution of Abell clusters within $300~$Mpc/h the…
This work explores the role of thermodynamic fluctuations in the two parameter giant and superstar configurations characterized by an ensemble of arbitrary liquid droplets or irregular shaped fuzzballs. Our analysis illustrates that the…
We present new results of our wide-field redshift survey of galaxies in a 182 square degree region of the Shapley Supercluster (SSC) based on observations with the FLAIR-II spectrograph on the UK Schmidt Telescope. We present new…