Revealing the influence of dark matter on the nature of motion and the families of orbits in axisymmetric galaxy models

Zotos, Euaggelos E.; Caranicolas, N. D.

doi:10.1051/0004-6361/201322352

Cited by 13 publications

(12 citation statements)

References 21 publications

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“…Thus, we can easily identify the various families of regular orbits and also recognize the secondary resonances that bifurcate from them. The very same algorithm was used in several previous related papers (e.g., [42,15,40,41]).…”

Section: Figure Typementioning

confidence: 99%

Classifying orbits in the classical Hénon–Heiles Hamiltonian system

Zotos

2014

Nonlinear Dyn

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The Hénon-Heiles potential is undoubtedly one of the most simple, classical and characteristic Hamiltonian systems. The aim of this work is to reveal the influence of the value of the total orbital energy, which is the only parameter of the system, on the different families of orbits, by monitoring how the percentage of chaotic orbits, as well as the percentages of orbits composing the main regular families evolve when energy varies. In particular, we conduct a thorough numerical investigation distinguishing between ordered and chaotic orbits, considering only bounded motion for several energy levels. The smaller alignment index (SALI) was computed by numerically integrating the equations of motion as well as the variational equations to extensive samples of orbits in order to distinguish safely between ordered and chaotic motion. In addition, a method based on the concept of spectral dynamics that utilizes the Fourier transform of the time series of each coordinate is used to identify the various families of regular orbits and also to recognize the secondary resonances that bifurcate from them. Our exploration takes place both in the physical (x, y) and the phase (y,ẏ) space for a better understanding of the orbital properties of the system. It was found, that for low energy levels the motion is entirely regular being the box orbits the most populated family, while as the value of the energy increases chaos and several resonant families appear. We also observed, that the vast majority of the resonant orbits belong in fact in bifurcated families of the main 1:1 resonant family. We have also compared our results with previous similar outcomes obtained using different chaos indicators.

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Section: Figure Typementioning

confidence: 99%

Classifying orbits in the classical Hénon–Heiles Hamiltonian system

Zotos

2014

Nonlinear Dyn

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“…Galactic dynamics is of paramount importance not only because of the evident astronomical interest in classifying and analyzing the nature of galaxies (Binney & Tremaine 2008;Manos & Athanassoula 2011;Zotos 2012), but also to investigate the nature of dark matter that constitutes a significant part of these objects (Zotos & Caranicolas 2013). Exploring the nature of orbits on different models of galaxies can provide a hint to the nature of dark matter present in these structures.…”

Section: Introductionmentioning

confidence: 99%

Orbit classification in a disk galaxy model with a pseudo-Newtonian central black hole

Zotos

Dubeibe

Steklain

et al. 2020

A&A

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We numerically investigate the motion of stars on the meridional plane of an axially symmetric disk galaxy model, containing a central supermassive black hole, represented by the Paczyński-Wiita potential. By using this pseudo-Newtonian potential we can replicate important relativistic properties such as the existence of the Schwarzschild radius. After classifying extensive samples of initial conditions of trajectories, we managed to distinguish between collisional, ordered, and chaotic motion. Besides all starting conditions of regular orbits were further classified into families of regular orbits. Our results are presented via color-coded basin diagrams on several types of two-dimensional planes. Our analysis reveals that both the mass of the black hole (in direct relation with the Schwarzschild radius) as well as angular momentum play an important role in the character of the orbits of stars. More specifically, the trajectories of low angular momentum stars are highly affected by the mass of the black hole, while high angular momentum stars seem to be unaffected by the central black hole. A comparison with previous related outcomes, using Newtonian potentials for the central region of the galaxy, is also made.

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“…al., 2012, Manos et al, 2013 or the influence of the galaxy components (nucleus, bulge, disk, halo) on the character of orbits, see e.g. (Zotos, 2012, Zotos & Caranicolas, 2013, Zotos, 2014. Notwithstanding the evidence that both chaotic and regular motions are possible in many axisymmetric potentials, recent studies on generalized axisymmetric potentials suggest that a third integral of motion seems to exist for energy values closer to the escape energy (Dubeibe et al, 2018.…”

Section: Introductionmentioning

confidence: 99%

Orbital dynamics in realistic galaxy models: NGC 3726, NGC 3877 and NGC 4010

Dubeibe

Martínez-Sicachá

González

2019

Rev. Acad. Colomb. Cienc. Ex. Fis. Nat.

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In the present paper, using a generalization of the Miyamoto and Nagai potential we adjusted the observed rotation curves of three specific spiral galaxies to the analytical circular velocities. The observational data have been taken from a 21 cm-line synthesis imaging survey using the Westerbork Synthesis Radio Telescope, for three particular galaxies in the Ursa Major cluster: NGC 3726, NGC 3877 and NGC 4010. Accordingly, the dynamics of the system is analyzed in terms of the Poincaré sections method, finding that for larger values of the angular momentum of the test particle or lower values its total energy the dynamics is mainly regular, while on the opposite cases, the dynamics is mainly chaotic. Our toy model opens the possibility to find chaotic bounded orbits for stars in those particular galaxies.Dinámica orbital en modelos realistas de galáxias: NGC 3726, NGC 3877 y NGC 4010 ResumenEn el presente trabajo, utilizando una generalización del potencial de Miyamoto-Nagai, se ajustan las curvas de rotación observadas de tres galaxias espirales a las velocidades circulares analíticas. Los datos observacionales se tomaron de un conjunto de imágenes de línea de 21 centímetros (o línea HI) obtenidos con el Westerbork Synthesis Radio Telescope (WSRT), para tres galaxias particulares en el grupo de la Ursa Major: NGC 3726, NGC 3877 y NGC 4010. Seguidamente, se analiza la dinámica del sistema en términos del método de secciones de Poincaré, encontrando que para valores grandes del momento angular de la partícula de prueba o valores bajos su energía total, la dinámica es principalmente regular, mientras que en los casos opuestos, la dinámica es principalmente caótica. Nuestro modelo abre la posibilidad de encontrarórbitas caóticas acotadas para estrellas presentes en esas galaxias particulares.Palabras clave: Dinámica estelar, Galaxias: cinemática y dinámica, Dinámica no lineal y caos.

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Revealing the influence of dark matter on the nature of motion and the families of orbits in axisymmetric galaxy models

Cited by 13 publications

References 21 publications

Classifying orbits in the classical Hénon–Heiles Hamiltonian system

Classifying orbits in the classical Hénon–Heiles Hamiltonian system

Orbit classification in a disk galaxy model with a pseudo-Newtonian central black hole

Orbital dynamics in realistic galaxy models: NGC 3726, NGC 3877 and NGC 4010

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