Related papers: Three Mechanisms for Bar Thickening
We analyze evolution of live disk-halo systems in the presence of various gas fractions, f_gas less than 8% in the disk. We addressed the issue of angular momentum (J) transfer from the gas to the bar and its effect on the bar evolution. We…
A significant fraction of barred spiral galaxies exhibits peanut/X-shaped structures in their central regions. Bars are known to rotate with a single pattern speed, and they eventually slow down over time due to the dynamical friction with…
We explore trends in the morphology and line-of-sight (los) velocity of stellar populations in the inner regions of disc galaxies, using N-body simulations with both a thin (kinematically cold) and a thick (kinematically hot) disc which…
I decompose the unstable growing modes of stellar disks to their Fourier components and present the physical mechanism of instabilities in the context of resonances. When the equilibrium distribution function is a non-uniform function of…
A method which we have developed for determining corotation radii, has allowed us to map in detail the radial resonant structures of barred spiral galaxies. Here we have combined this information with new determinations of the bar strength…
This chapter reviews theoretical work on the stellar dynamics of galaxy disks. All the known collective global instabilities are identified, and their mechanisms described in terms of local wave mechanics. A detailed discussion of warps and…
This is the first paper of a series aimed to understand the formation and evolution of bars in early-type spirals and their influence in the evolution of the galaxy. Optical long-slit spectra along the major axis of the bar of a sample of…
Galactic bars are found in the majority of disc galaxies. They rotate nearly rigidly with an angular frequency called pattern speed. Previous idealised simulations have shown that bar pattern speed decreases with time due to dynamical…
We analyze how the orbital support of the inner bar in a double-barred galaxy (nested bars) depends on the angular velocity (i.e. pattern speed) of this bar. We study orbits in seven models of double bars using the method of invariant…
Galactic bars and their associated resonances play a significant role in shaping galaxy evolution. Resulting resonance-driven structures, like the vertically extended Boxy/Peanut X-Feature (BPX), then serve as a useful probe of the host…
Inner regions of barred disk galaxies often include asymmetrical, small-scale central features, some of which are best described as secondary bars. Because orbital timescales in the galaxy center are short, secondary bars are likely to be…
We show that stable double-frequency orbits form the backbone of double bars, because they trap around themselves regular orbits, as stable closed periodic orbits do in single bars, and in both cases the trapped orbits occupy similar volume…
We study the conditions that favour boxiness of isodensities in the face-on views of orbital 3D models for barred galaxies. Using orbital weighted profiles we show that boxiness is in general a composite effect that appears when one…
(Edited) Many fast rotator stars (rotation periods of < 2 days) are found in unresolved binaries with separations of tens of au. This correlation leads to the question of whether the formation of binary stars inherently produces fast…
More than two thirds of disk galaxies are barred to some degree. Many today harbor massive concentrations of gas in their centers, and some are known to possess supermassive black holes (SMBHs) and their associated stellar cusps. Previous…
Dynamical evolution of spiral galaxies is strongly dependent on non-axisymmetric patterns that develop from gravitational instabilities, either spontaneously or externally triggered. Some evolutionary sequences are described through which a…
The arising of turbulence in gas-dynamic (non-magnetic) accretion disks is a major issue of modern astrophysics. Such accretion disks should be stable against the turbulence generation, in contradiction to observations. Searching for…
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…
We track the angular momentum transfer in n-body simulations of barred galaxies by measuring torques to understand the dynamical mechanisms responsible for the evolution of the bar-disc-dark matter halo system. We find evidence for three…
Galaxy surveys have suggested that rapid and sustained decrease in the star-formation rate, "quenching", in massive disk galaxies is frequently related to the presence of a bar. Optical and near-IR observations reveal that nearly 60% of…