Related papers: The parallelism between galaxy clusters and early-…
The relaxation time at the half-mass radius of Galactic globular clusters (GGCs) is typically within a few Gyr. Hence, the majority of GGCs are expected to be well relaxed systems, given their age is around 12-13 Gyr. So any initial radial…
We revisit the color-magnitude relation (CMR) of the Virgo cluster early-type galaxies in order to explore its alleged non-linearity. To this aim, we reanalyze the relation already published from data obtained within the ACS Virgo Cluster…
The bottom line of this study is (i) to check whether normal (quiescent) and interacting EGs have a different behavior in the popular diagnostic planes such as Hb vs. [MgFe] (and others); (ii) to seek whether the signature of mergers and/or…
We test the hypothesis that globular clusters form in supergiant molecular clouds within high-redshift galaxies. Numerical simulations demonstrate that such large, dense, and cold gas clouds assemble naturally in current hierarchical models…
The mass function of galaxies and clusters of galaxies can be derived observationally based on different types of observations. In this study we test if these observations can be combined to a consistent picture which is also in accord with…
We present an overview of observational progress in the study of extragalactic globular cluster systems. Globular clusters turn out to be excellent tracers not only for the star-formation histories in galaxies, but also for kinematics at…
Maximizing the utility of upcoming photometric cluster surveys requires a thorough understanding of the richness-mass relation of galaxy clusters. We use Monte Carlo simulations to study the impact of various sources of observational…
Keck spectroscopy and Hubble Space Telescope WFPC2 imaging over a 1.5x1.5 Mpc field of CL1358+62 at z=0.33 are used to study the Fundamental Plane of galaxies based on a new, large sample of 53 galaxies. First, we have constructed the…
At which masses does the regime of globular clusters end and the one of dwarf galaxies begin? And what separates these two classes of hot stellar systems? We examine to what extend very massive (>10^7 Mo) young star clusters are similar to…
In addition to their low stellar densities, ultra-diffuse galaxies (UDGs) have a broad variety of dynamical mass-to-light ratios, ranging from dark matter (DM) dominated systems to objects nearly devoid of DM. To investigate the origin of…
Observations consistently show that elliptical galaxies follow a tight "fundamental plane" scaling relation between size, mean surface brightness and velocity dispersion, with the form $R \propto \sigma^{a}\mu^{b}$. This relation not only…
We estimated the dynamical masses of 115 early-type galaxies (ETGs) by analyzing the dynamics of satellite and companion galaxies of these ETGs. We selected galaxies with absolute magnitudes between -22 and -25 in the $K_s$-band from the…
We use stellar masses, photometry, lensing, and velocity dispersions to investigate empirical correlations for the final sample of 73 early-type lens galaxies (ETGs) from the SLACS survey. The traditional correlations (Fundamental Plane…
Spatial clustering nature of galaxies have been studied previously through auto correlation function. The same type of cross correlation function has been used to investigate parametric clustering nature of galaxies e.g. with respect to…
We discover alignment of galaxies in clusters by analyzing the distribution of their position angles. We assume that galaxies are aligned, if their number at one 90deg position angle interval is more than twice higher than at another 90deg…
Globular Cluster (GC) systems of most early-type galaxies show bimodal optical color distributions, yet their Luminosity Functions (LFs) look like simple Gaussians with turn-over magnitudes used for determination of distances and the Hubble…
Properties of 53 globular cluster systems are investigated. Strong correlations are found between parent galaxy luminosity and both the slope of the radial density profile for clusters and the width of the cluster color (metallicity)…
Stellar obliquity ($\lambda$) and orbital eccentricity ($e$) trace the dynamical histories of close-in giant planets, but the current observational picture is assembled from heterogeneous analyses that have obscured population-level trends.…
The metallicity distributions of globular cluster (GC) systems in galaxies are a critical test of any GC formation scenario. In this work, we investigate the predicted GC metallicity distributions of galaxies in the MOdelling Star cluster…
We study the orbits of the various types of galaxies observed in the ESO Nearby Abell Cluster Survey. Galaxies within and outside substructures are considered separately. We use the mass profile we determined from the distribution and…