Related papers: Slowly rotating bars-Morphologies introduced by bi…
We have modelled the nonlinear development of the secular bar-mode instability that is driven by gravitational radiation-reaction (GRR) forces in rotating neutron stars. In the absence of any competing viscous effects, an initially…
We find that a steady state bar induces transient features at low velocities in the solar neighborhood velocity distribution due to the initial response of the disc, following the formation of the bar. We associate these velocity streams…
We investigate the stellar masses of strongly barred spiral galaxies. Our analysis is based on a sample of ~14000 visually-classified nearby galaxies given in Nair & Abraham 2010(a). The fraction of barred spiral galaxies is found to be a…
We examine the idea that dynamical parameters can be estimated by identifying locations in the solar neighbourhood where simulated velocity distributions match the observed local distribution. Here, the dynamical influence of both the…
In this paper I describe numerical calculations of the motion of particles in a disk about a solar-mass object perturbed by a planet on a circular orbit with mass greater than 0.001 of the stellar mass. A simple algorithm for simulating…
The arguments in favor of the unified formation mechanism for both slow (Lynden-Bell's) bars and common fast bars are given. This mechanism consists in a certain instability that is akin to the well-known radial orbit instability; it is…
ESO 566-24 is an extraordinary barred galaxy, which has four regularly spaced spiral arms in blue light images. This type of four-armed spiral structure, which is rare among the spiral population, is clearly seen also in near-infrared…
Theories that attempt to explain the dynamical relationship between bar and spiral patterns in galactic disks make different predictions about the radial profile of the pattern speed. These are tested for the H-alpha bar and spiral patterns…
Nonbarred ringed galaxies are relatively normal galaxies showing bright rings of star formation in spite of lacking a strong bar. This morphology is interesting because it is generally accepted that a typical ring forms when material…
Secular evolution gradually shapes galaxies by internal processes, in contrast to early cosmological evolution which is more rapid. An important driver of secular evolution is the flow of gas from the disk into the central regions, often…
Galactic bars can form via the internal bar instability or external tidal perturbations by other galaxies. We systematically compare the properties of bars formed through the two mechanisms with a series of controlled $N$-body simulations…
We analyze previous results on the stability of uniformly and differentially rotating, self-gravitating, gaseous and stellar, axisymmetric systems to derive a new stability criterion for the appearance of toroidal, m=2 Intermediate (I) and…
We present MUSE integral field stellar and ionized velocity maps for a sample of 14 barred galaxies. Most of these objects exhibit "S"-shape iso-velocities in the bar region indicative of the presence of streaming motions in the velocity…
Dust lanes, nuclear rings, and nuclear spirals are typical gas structures in the inner region of barred galaxies. Their shapes and properties are linked to the physical parameters of the host galaxy. We use high-resolution hydrodynamical…
We run N-body smoothed particle hydrodynamics (SPH) simulations of a Milky Way sized galaxy. The code takes into account hydrodynamics, self-gravity, star formation, supernova and stellar wind feedback, radiative cooling and metal…
Boxy edge-on profiles can be accounted for not only in models of barred galaxies, but also in models of normal (non-barred) galaxies. Thus, the presence of a bar is not a sine qua non condition for the appearance of this feature, as often…
We show by numerical simulations that a purely stellar dynamical model composed of an exponential disc, a cuspy bulge, and an NFW halo with parameters relevant to the Milky Way Galaxy is subject to bar formation. Taking into account the…
The central theme of this thesis work is to explore the possibilities of spiral arm formations from instabilities formed inside the central region of disc galaxies. These instabilities originate from the central baryonic feedback and have…
Strong galactic bars produced in simulations tend to undergo a period of buckling instability that weakens and thickens them and forms a boxy/peanut structure in their central parts. This theoretical prediction has been confirmed by…
Does the environment of a galaxy directly influence the kinematics of its bar? We present observational evidence that bars in high-density environments exhibit significantly slower rotation rates than bars in low-density environments.…