Related papers: The radial acceleration relation in galaxy cluster…
`Conspiracy' between the dark and the baryonic mater prohibits an unambiguous decomposition of disc galaxy rotation curves into the corresponding components. Several methods have been proposed to counter this difficulty, but their results…
General Relativity is able to describe the dynamics of galaxies and larger cosmic structures only if most of the matter in the Universe is dark, namely it does not emit any electromagnetic radiation. Intriguingly, on the scale of galaxies,…
The widely known relation between stellar mass and gas metallicity (mass-metallicity relation, MZR) in galaxies is often ascribed to the higher capability of more massive systems to retain metals against the action of galactic outflows. In…
The different dynamical processes (relaxation, dynamical friction, tides and mergers) operating in groups and clusters are reviewed. The small-scale substructure observed in clusters is argued to be the remnants of the cores of rich…
The mass derived from gravitational lensing reflects the total mass contained in the lensing system, independent of the specific matter contents and states. A comparison of the dynamical masses from hydrostatic equilibrium with the…
The Galactic Anticenter Stellar Structure (GASS) has been identified with excess surface densities of field stars in several large area sky surveys, and with an unusual, string-like grouping of star clusters. Some members of the cluster…
The abundance and internal characteristics of rich clusters of galaxies can provide useful constraints on models of large--scale structure formation. This article will review some recent three dimensional, multi--fluid simulations of…
In this contribution, we review our current knowledge of the properties of galaxies, and their extended halos, selected by MgII absorption in the spectra of background quasars. We then describe recent efforts to quantify the morphologies…
Stars form predominantly in groups usually denoted as clusters or associations. The observed stellar groups display a broad spectrum of masses, sizes and other properties, so it is often assumed that there is no underlying structure in this…
[Abridged] We present an analysis of the relation between the masses of cluster- and group-sized halos, extracted from $\Lambda$CDM cosmological N-body and hydrodynamic simulations, and their velocity dispersions, at different redshifts…
Observations of stars in the the solar vicinity show a clear tendency for old stars to have larger velocity dispersions. This relation is called the age-velocity dispersion relation (AVR) and it is believed to provide insight into the…
We quantify the expected observed statistical and systematic uncertainties of the escape velocity as a measure of the gravitational potential and total mass of galaxy clusters. We focus our attention on low redshift (z < 0.15) clusters,…
[Abridged] In the past 15 years, the concentration-mass relation has been investigated diffusely in theoretical studies. On the other hand, only recently has this relation been derived from X-ray observations. When that happened, the…
The Scale-Invariant Vacuum (SIV) theory is based on Weyl's Integrable Geometry, endowed with a gauge scalar field. The main difference between MOND and the SIV theory is that the first considers a global dilatation invariance of space and…
If the accelerated expansion of the universe is due to a modification of general relativity at late times, it is likely that the growth of structure on large scales would also display deviations from the standard cosmology. We investigate…
The mass of galaxy clusters is a critical quantity for probing cluster cosmology and testing theories of gravity, but its measurement could be biased given assumptions are inevitable. In this paper, we employ and compare two mass proxies…
Here I report the scaling relation between the baryonic masses and the scale lengths of stellar discs from $\sim$1000 morphologically late-type galaxies. The baryonic mass-size relation is a single power-law $R_\ast \propto M_b^{0.38}$…
Recent studies in different types of galaxies reveal that the product of the central density and the core radius ($\rho_cr_c$) is a constant. However, some empirical studies involving galaxy clusters suggest that the product $\rho_cr_c$…
I review our understanding of classic dynamical scaling relations, relating luminosity, size and kinematics of early-type galaxies. Using unbiased determinations of galaxy mass profiles from stellar dynamical models, a simple picture has…
In cold dark matter cosmology, the baryonic components of galaxies are thought to be mixed with and embedded in non-baryonic and non-relativistic dark matter, which dominates the total mass of the galaxy and its dark matter halo. In the…