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Using the canonical Hamilton-Jacobi approach we study the Lynden-Bell concept of bar formation based on the idea of orbital trapping parallel to the long or short axes of the oval potential distortion. The concept considered a single…

Astrophysics of Galaxies · Physics 2020-09-02 E. V. Polyachenko , I. G. Shukhman

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…

Astrophysics · Physics 2007-05-23 E. V. Polyachenko , V. L. Polyachenko

For the first time, we investigate the resonant structure of $N$-body galactic bar at the stage of buckling using action-angle variables. We studied the evolution of vertical actions ($J_z$) and angles associated with vertical resonance…

Astrophysics of Galaxies · Physics 2025-06-05 Viktor D. Zozulia , Natalia Ya. Sotnikova , Anton A. Smirnov

In a time-orbiting-potential magnetic trap the neutral atoms are confined by means of an inhomogeneous magnetic field superimposed to an uniform rotating one. We perform an analytic study of the atomic motion by taking into account the…

Soft Condensed Matter · Physics 2009-11-10 Roberto Franzosi , Andrea Spinelli , Bruno Zambon , Ennio Arimondo

Using N-body simulations, we study the properties of a bar induced in a dwarf galaxy as a result of tidal interaction with the Milky Way. The dwarf is initially composed of a disk embedded in a dark matter halo and we follow its evolution…

Astrophysics of Galaxies · Physics 2015-10-12 E. L. Lokas , E. Athanassoula , V. P. Debattista , M. Valluri , A. del Pino , M. Semczuk , G. Gajda , K. Kowalczyk

In the present work we have developed a three-dimensional gravitational model of barred galaxies, in order to study orbital and escape dynamics of the stars inside their central barred region. Our gravitational model is composed of four…

Astrophysics of Galaxies · Physics 2021-09-29 Debasish Mondal , Tanuka Chattopadhyay

Current theories of dynamical friction on galactic bars are based either on linear perturbation theory, which is valid only in the fast limit where the bar changes its pattern speed rapidly, or on adiabatic theory, which is applicable only…

Astrophysics of Galaxies · Physics 2023-08-04 Rimpei Chiba

We investigate the orbital structure in a class of 3D models of barred galaxies. We consider different values of the pattern speed, of the strength of the bar and of the parameters of the central bulge of the galactic model. The morphology…

Astrophysics · Physics 2009-11-07 Ch. Skokos , P. A. Patsis , E. Athanassoula

In this paper we use the two-dimensional (2D) version of a new analytical gravitational model in order to explore the orbital as well as the escape dynamics of the stars in a barred galaxy composed of a spherically symmetric central…

Astrophysics of Galaxies · Physics 2016-04-13 Christof Jung , Euaggelos E. Zotos

Lynden-Bell & Kalnajs (1972) presented a useful formula for computing the long-range torque between spiral arms and the disk at large. The derivation uses second-order perturbation theory and assumes that the perturbation slowly grows over…

Astrophysics · Physics 2007-05-23 Martin D. Weinberg

The method to study oscillating potentials of double bars, based on invariant loops, is introduced here in a new way, intended to be more intelligible. Using this method, I show how the orbital structure of a double-barred galaxy (nested…

Astrophysics of Galaxies · Physics 2009-03-17 Witold Maciejewski

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…

Astrophysics of Galaxies · Physics 2017-06-28 Grzegorz Gajda , Ewa L. Lokas , E. Athanassoula

Orbits are the key building blocks of any density distribution and their study helps us understand the kinematical structure and the evolution of galaxies. Here we investigate orbits in a tidally induced bar of a dwarf galaxy, using an…

Astrophysics of Galaxies · Physics 2016-10-21 Grzegorz Gajda , Ewa L. Lokas , E. Athanassoula

Secular evolution is one of the key routes through which galaxies evolve along the Hubble sequence. Not only the disk undergoes morphological and kinematic changes, but also a preexisting classical bulge may be dynamically changed by the…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-28 Kanak Saha , Inma Martinez-Valpuesta , Ortwin Gerhard

We study vertical resonant trapping and resonant heating of orbits. These two processes both lead to the growth of a boxy/peanut-shaped bulge in a typical $N$-body model. For the first time, we study this by means of the action variables…

Astrophysics of Galaxies · Physics 2024-11-18 Viktor D. Zozulia , Anton A. Smirnov , Natalia Ya. Sotnikova , Alexander A. Marchuk

We investigate the dynamical response of stellar orbits in a rotating barred galaxy potential to the perturbation by a nuclear gaseous ring. The change in 3D periodic orbit families is examined as the gas accumulates near the inner Lindblad…

Astrophysics · Physics 2007-05-23 C. H. Heller , I. Shlosman

We investigate the adiabatic orbital evolution of a point particle in the Kerr spacetime due to the emission of gravitational waves. In the case that the timescale of the orbital evolution is enough smaller than the typical timescale of…

General Relativity and Quantum Cosmology · Physics 2009-11-11 Norichika Sago , Takahiro Tanaka , Wataru Hikida , Katsuhiko Ganz , Hiroyuki Nakano

We investigate the evolution of orbital shapes at the Inner Lindblad Resonance region of a rotating three-dimensional bar, the mass of which is growing with time. We evaluate in time-dependent models, during a 5 Gyr period, the importance…

Astrophysics of Galaxies · Physics 2021-10-27 Thanos Manos , Charalampos Skokos , Panos Patsis

The classical model that describes the motion of an atom in a magnetic trap is solved in order to investigate the relationship between the failure of the usual adiabatic approximation assumption and the physical parameters of the trap. This…

Quantum Gases · Physics 2015-05-18 Bruno Zambon , Roberto Franzosi

We investigate the orbital dynamics of a \textit{barred-spiral} model when the system is rotating slowly and corotation is located beyond the end of the spiral arms. In the characteristic of the central family of periodic orbits we find a…

Astrophysics of Galaxies · Physics 2015-06-23 L. Tsigaridi , P. A. Patsis
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