相关论文: Formation of rings in galactic discs by infalling …

We investigate the dynamical effects of an interaction between an initially barred galaxy and a small spherical companion using an N-body/SPH algorithm. In the models described here the small companion passes through the disc of the larger…

Disc galaxies can be substantially modified by close encounters and mergers, since their discs are very responsive components. Close interactions can be held responsible for the formation of bridges and tails, as well as for the formation…

Using an N-body+SPH code we have performed numerical simulations to investigate the dynamical effects of an interaction between an initially barred galaxy and a small spherical companion. In the models described here the small companion…

I discuss results from the COSMOS survey, showing that the fraction of disc galaxies that is barred decreases considerably with look-back time from z ~ 0.2 to z ~ 0.8. This decrease is more important for small mass and low luminosity…

Many disc galaxies host galactic bars, which exert time-dependent, non-axisymmetric forces that can alter the orbits of stars. There should be both angle and radius-dependence in the resulting radial rearrangement of stars ('radial mixing')…

In this and in a previous paper (Romero-Gomez et al. 2006) we propose a theory to explain the formation of both spirals and rings in barred galaxies using a common dynamical framework. It is based on the orbital motion driven by the…

In this review we consider various ring structures that are observed in galaxies. Formation and evolution of the rings are interesting problems in studies of galactic morphology. They are related to such fundamental aspects of galactic…

We propose a theory to explain the formation of both spirals and rings in barred galaxies using a common dynamical framework. It is based on the orbital motion driven by the unstable equilibrium points of the rotating bar potential. Thus,…

Bars in galaxies may develop through a global instability or due to an interaction with another system. We study bar formation in disky dwarf galaxies orbiting a Milky Way-like galaxy. We employ $N$-body simulations to study the impact of…

Aims. We aim to show how encounters with low-mass satellite galaxies may alter the bar formation in a Milky Way-like disc galaxy. Methods. We use high-resolution N-body simulations of a disc galaxy prone to mild bar instability. For…

Most stars form in a clustered environment. Therefore, it is important to assess how this environment influences the evolution of protoplanetary discs around young stars. In turn, this affects their ability to produce planets and ultimately…

The recent discovery of narrow rings around minor bodies has raised many questions regarding their origin and current dynamics. Sharp ring boundaries seem indicative of shepherding moonlets, but none have been found. All rings lie close to…

We discuss the evolution of a disc galaxy due to the formation of a bar and, subsequently, a peanut. After the formation stage there is still considerable evolution, albeit slower. In purely stellar cases the pattern speed of the bar…

In this paper I argue that, far from necessarily hindering bar formation in disc galaxies, inner haloes may stimulate it. This constitutes a new instability mechanism by which bars can grow. To show this I use a number of N-body simulations…

N-body simulations of galactic collisions are employed to investigate the formation of elliptical rings in disk galaxies. The relative inclination between disk and dwarf galaxies is studied with a fine step of five degrees. It is confirmed…

It appears that most stars are born in clusters, and that at birth most stars have circumstellar discs which are comparable in size to the separations between the stars. Interactions between neighbouring stars and discs are therefore likely…

The emergence of a large-scale stellar bar is one of the most striking features in disc galaxies. By means of state-of-the-art cosmological zoom-in simulations, we study the formation and evolution of bars in Milky Way-like galaxies in a…

Bars in galaxies may form not only through instability, but also as a result of an interaction with another galaxy. In particular, they may appear in disky dwarf galaxies interacting with Milky Way-like galaxies. Here we report the results…

For several decades it has been known that stellar bars in disc galaxies can be triggered by interactions, or by internal processes such as dynamical instabilities. In this work, we explore the differences between these two mechanisms using…

From this vast subject, I will pick out and review three specific topics, namely the formation and evolution of bars, the formation of bulges, and the evolution during multiple major mergers. Bars form naturally in galactic discs. Their…