Related papers: Notes on counter-orbiting globular clusters in the…
Recent investigations of the double red clump in the color-magnitude diagram of the Milky Way bulge cast serious doubts on the structure and formation origin of the outer bulge. Unlike previous interpretation based on an X-shaped bulge,…
The cause of the extended rotation curves of galaxies is investigated. It is shown that conventional sources and most exotic sources for the needed gravitational fields are implausible. We suggest spatial fluctuations in a scalar field,…
We investigate, by means of numerical simulations, the possibility of forming counter-rotating old stellar components by major mergers between an elliptical and a spiral galaxy. We show that counter-rotation can appear both in dissipative…
Nikos Voglis had many astronomical interests, among them was the question of the origin of galactic angular momentum. In this short tribute we review how this subject has changed since the 1970's and how it has now become evident that…
Galaxies and galaxy clusters are observed to have a rather non-trivial radial behaviour. The observations show that the radial profiles change from one power-law profile near the centre to another power-law profile in the outer region. We…
Globular cluster populations of supergiant elliptical galaxies are known to vary widely, from extremely populous systems like that of UGC 9799, the centrally dominant galaxy in Abell 2052, to globular-cluster-poor galaxies such as NGC 5629…
Nuclear Star Clusters are observed at the center of many galaxies. In particular in the center of the Milky Way the Nuclear Star Cluster coexists with a cen- tral supermassive black hole. The origin of these clusters is still unknown; a…
In the paper we discussed the observational aspects of rotation in the Universe on different scales. We show dependence between the angular momentum of the structures and their size. The presented observational situation is that the…
Globular clusters are collisional systems, meaning that the stars inside them interact on timescales much shorter than the age of the Universe. These frequent interactions transfer energy between stars and set up observable trends that tell…
A growing number of Milky Way globular clusters have been identified to possess a noticeable degree of solid-body rotation. For several clusters, the combination of stellar proper motions and radial velocities allows for 3-dimensional spin…
The interpretation of the difference observed between the radial distribution of globular clusters and that of halo-bulge stars in elliptical galaxies is discussed in terms of evolution of their globular cluster systems. I present a short…
Globular cluster systems exhibit a bewildering variety of characteristics. No single scenario appears to be able to account for the wide range of specific globular cluster frequencies that are observed in galaxies of various types. The…
We have studied the system of globular clusters (GCs) that formed in other galaxies and eventually accreted onto the Milky Way. Thus, the samples of GCs belonging to different tidal streams, obtained on the basis of the latest data from the…
There is increasing evidence that a substantial fraction of Milky Way satellite galaxies align in a rotationally-supported plane of satellites, a rare configuration in cosmological simulations of galaxy formation. It has been suggested that…
Motivated by recent studies suggesting that the Large Magellanic Cloud (LMC) could be significantly more massive than previously thought, we explore whether the approximation of an inertial Galactocentric reference frame is still valid in…
This review focuses on how galaxies and their globular cluster systems form. I first discuss the now fairly convincing evidence that some globular clusters form in galaxy starbursts/mergers. One way these observations are valuable is they…
Dynamical friction due to field stars and tidal disruption caused by a central nucleus are crucial in determining the evolution of the globular cluster system in an elliptical galaxy. In this paper I examine the possibility that some of…
The radial distribution of globular clusters in galaxies is always less peaked to the centre than the halo stars'. Extending previous work to a sample of HST globular cluster systems in ellipticals, we evaluate the number of clusters lost…
We report on the search for overall kinematical or structural conditions that have allowed some Milky Way globular clusters to presently develop tidal tails. For this purpose, we build a comprehensive catalogue of globular clusters with…
The effect of the global rotation of the universe on the formation of galaxies is investigated. It is found that the global rotation provides a natural origin for the rotation of galaxies, and the morphology of the objects formed from…