Related papers: Triplets of Galaxies: Some Dynamical Aspects
We examine the peculiar velocity distribution function of galaxies in cosmological many-body gravitational clustering. Our statistical mechanical approach derives a previous basic assumption and generalizes earlier results to galaxies with…
Stellar shells observed in many giant elliptical and lenticular as well as a few spiral and dwarf galaxies presumably result from radial minor mergers of galaxies. We show that the line-of-sight velocity distribution of the shells has a…
The evolution of galaxies is driven strongly by dynamical processes including internal instabilities, tidal interactions and mergers. The cluster environment is a useful laboratory for studying these effects. I present recent results on…
Dynamical evolution of stellar mass distribution in star clusters is analysed by considering simultaneously the effects of dynamical friction, stochastic heating and the gravitational potential due to mass distribution in the clusters. A…
The process of galaxy cluster formation likely leaves an imprint on the properties of its individual member galaxies. Understanding this process is essential for uncovering the evolutionary connections between galaxies and cosmic…
The properties of spatial distribution of luminous matter are investigated analysing all the available three dimensional catalogues of galaxies. In standard view, galaxies are believed to have a fractal distribution at small scale with a…
We analyse a sample of 71 triplets of luminous galaxies derived from the work of O'Mill et al. (2012). We compare the properties of triplets and their members with those of control samples of compact groups, the ten brightest members of…
Observed and simulated galaxies exhibit a significant variation in their velocity dispersion profiles. We examine the inner and outer slopes of stellar velocity dispersion profiles using integral field spectroscopy data from two surveys,…
The distributions of peculiar velocities of rich clusters and of groups of galaxies are investigated for different cosmological models and are compared with observations. Four cosmological models are studied: standard ($\Omega=1$) CDM,…
Our statistical studies comprise the mean relative velocity and velocity correlation for pairs of galaxies as a function of separation, and a bulk flow analysis determined on spheres of $10 h^{-1}$ $Mpc$ radius. In order to test the…
Over the last few decades, observational surveys have revealed that high-order multiple-star systems (e.g. triples, quadruples, etc.), and triples in particular, are common in our Galaxy. In this paper, we consider the dynamical…
Dynamical parameters like average velocity dispersion and temperature profile of galaxy clusters are determined using a quasi equilibrium thermodynamic theory. The calculated velocity dispersion results from theory and simulations shows a…
We investigate the dynamical evolution of galaxies in groups with different formation epochs. Galaxy groups have been selected to be in different dynamical states, namely dynamically old and dynamically young, which reflect their early and…
This work analyses the properties of groups of galaxies in the surroundings of clusters. On the basis of a very large public Virgo Consortium Simulation, we identified systems of galaxies in a wide range of masses. Systems with masses…
Taking advantage of a high-resolution simulation coupled with a state-of-art semi-analytic model of galaxy formation, we probe the mass segregation of galaxies in groups and clusters, focusing on which physical mechanisms are driving it. We…
The velocity dispersion of galaxies on small scales ($r\sim1h^{-1}$ Mpc), $\sigma_{12}(r)$, can be estimated from the anisotropy of the galaxy-galaxy correlation function in redshift space. We apply this technique to ``mock-catalogs''…
After a recall of fundamental concepts used in galactic dynamics, we review observational facts as well as results of orbit theory and numerical simulations which suggest long-term evolution of galaxies. Dynamical interactions between…
A program is outlined, and first results described, in which fully three-dimensional, time dependent simulations of hydrodynamic turbulence are used as a basis for theoretical investigation of the physics of turbulence in stars. The…
Close pairs of galaxies have been broadly studied in the literature as a way to understand galaxy interactions and mergers. In observations they are usually defined by setting a maximum separation in the sky and in velocity along the line…
The kinematics of galaxies with 10 megaparsecs (10 Mpc) of the Milky Way is investigated using published distances and radial velocities. With respect to the average Hubble flow (isotropic or simple anisotropic), there is NO systematic…