Related papers: Dynamically possible pattern speeds of double bars
Nonlinear growth of the bar-mode deformation is studied for a differentially rotating star with supercritical rotational energy. In particular, the growth mechanism of some azimuthal modes with odd wave numbers is examined by comparing a…
Implementing a family of differential rotation laws inspired by binary neutron-star merger remnants, we consider the impact of the rotation profile on the low-T/W instability. We use time evolutions of the linearised dynamical equations, in…
Using a volume- and mass-limited (D < 30 Mpc, log (M_star/M_sun) $\geq 9.75$) sample of 155 barred S0-Sd galaxies, I determine the fraction with secondary structures within their bars. Some 20 +/- 3% have a separate inner bar, making them…
Eccentricity of binary systems is not a gauge invariant quantity, but has an important impact on the observed gravitational wave signal of such systems, generating power in all possible harmonics of the orbital period. We here clarify the…
The dynamics of a barred galaxy depends on the pattern speed of its bar. The only direct method for measuring the pattern speed of a bar is the Tremaine-Weinberg technique. This method is best suited to the analysis of the distribution and…
The dynamics of a barred galaxy depends on the angular velocity or pattern speed of its bar. Indeed, it is related to the location of corotation where gravitational and centrifugal forces cancel out in the rest frame of the bar. The only…
We investigate the relations between the properties of bars and their host galaxies in a sample of 77 nearby barred galaxies, spanning a wide range of morphological types and luminosities, with 34 SB0-SBa and 43 SBab-SBc galaxies. The…
The buckling process in stellar bars is full of unsolved issues. We analyze the origin of the buckling instability in stellar bars using high-resolution N-body simulations. Previous studies have promoted the nonresonant firehose instability…
We study the kinematics of the barred spiral galaxy NGC 6946 by investigating the velocity field from H-alpha Fabry-Perot observations, determined the pattern speed of the bar by using the Tremaine-Weinberg method, and find a main pattern…
In this paper, the redshift evolution of the galactic bar properties, like the bar length, pattern speed, and bar fraction, has been investigated for simulated galaxies at stellar masses $M_*>10^{10}\, M_{\odot}$ in the cosmological…
We run hydrodynamical simulations of a 2D isothermal non self-gravitating inviscid gas flowing in a rigidly rotating externally imposed potential formed by only two components: a monopole and a quadrupole. We explore systematically the…
This paper aims to study the configuration of two components caused by rotational and tidal distortions in the model of a binary system. The potentials of the two distorted components can be approximated to 2nd-degree harmonics.…
Current theories of spiral and bar structure predict a variety of pattern speed behaviors, calling for detailed, direct measurement of the radial variation of pattern speeds. Our recently developed Radial Tremaine-Weinberg (TWR) method…
We examine the observable properties of simulated barred galaxies including radial mass profiles, edge-on structure and kinematics, bar lengths and pattern speed evolution for detailed comparison to real systems. We have run several…
This paper presents a numerical study over a wide parameter space of the likelihood of the dynamical bar-mode instability in differentially rotating magnetized neutron stars. The innovative aspect of this study is the incorporation of…
Most galaxies have a warped shape when they are seen from an edge-on point of view. The reason for this curious form is not completely known so far and in this work we apply dynamical system tools to contribute to its explanation. Starting…
A rapidly rotating, axisymmetric star can be dynamically unstable to an m=2 "bar" mode that transforms the star from a disk shape to an elongated bar. The fate of such a bar-shaped star is uncertain. Some previous numerical studies indicate…
The morphology of the outer rings of early-type spiral galaxies is compared to integrations of massless collisionless particles initially in nearly circular orbits. Particles are perturbed by a quadrupolar gravitational potential…
A one-armed spiral instability has been found to develop in differentially rotating stellar models that have a relatively stiff, $n=1$ polytropic equation of state and a wide range of rotational energies. This suggests that such…
A large fraction of barred galaxies host secondary bars that are embedded in their large-scale primary counterparts. These are common also in gas poor early-type barred galaxies. The evolution of such double-barred galaxies is still not…