scholarly journals Self-Consistent Gas and Stellar Dynamics of Disk Galaxies: A Problem of Dark Mass

2006 ◽  
pp. 337-343
Author(s):  
Alexander V. Khoperskov ◽  
Sergej S. Khrapov
Keyword(s):  
Stellar Dynamics ◽  
Disk Galaxies ◽  
Self Consistent

scholarly journals Stellar dynamics in the periodic cube

2021 ◽  
Vol 507 (4) ◽  
pp. 4840-4851
Author(s):  
John Magorrian
Keyword(s):  
Stellar Dynamics ◽  
Equal Mass ◽  
Linear Perturbation ◽  
Complex Frequency ◽  
Dynamical Friction ◽  
Linear Evolution ◽  
Real Frequency ◽  
Alternative Expression ◽  
Self Consistent ◽  
Consistent Response

ABSTRACT We use the problem of dynamical friction within the periodic cube to illustrate the application of perturbation theory in stellar dynamics, testing its predictions against measurements from N-body simulations. Our development is based on the explicitly time-dependent Volterra integral equation for the cube’s linear response, which avoids the subtleties encountered in analyses based on complex frequency. We obtain an expression for the self-consistent response of the cube to steady stirring by an external perturber. From this, we show how to obtain the familiar Chandrasekhar dynamical friction formula and construct an elementary derivation of the Lenard–Balescu equation for the secular quasi-linear evolution of an isolated cube composed of N equal-mass stars. We present an alternative expression for the (real-frequency) van Kampen modes of the cube and show explicitly how to decompose any linear perturbation of the cube into a superposition of such modes.

Study of starspots in fully convective stars using three dimensional MHD simulations

2018 ◽  
Vol 13 (S340) ◽  
pp. 303-304
Author(s):  
Arnab Basak ◽  
Dibyendu Nandy
Keyword(s):  
High Resolution ◽  
Numerical Simulations ◽  
High Latitude ◽  
Three Dimensional ◽  
Stellar Dynamics ◽  
The Sun ◽  
Dynamo Action ◽  
Magnetic Structures ◽  
Mhd Simulations ◽  
Self Consistent

AbstractConcentrated magnetic structures such as sunspots and starspots play a fundamental role in driving solar and stellar activity. However, as opposed to the sun, observations as well as numerical simulations have shown that stellar spots are usually formed as high-latitude patches extended over wide areas. Using a fully spectral magnetohydrodynamic (MHD) code, we simulate polar starspots produced by self-consistent dynamo action in rapidly rotating convective shells. We carry out high resolution simulations and investigate various properties related to stellar dynamics which lead to starspot formation.

scholarly journals Integration Methods where Force is Obtained from the Smoothed Gravitational Field

1971 ◽  
Vol 10 ◽  
pp. 168-178
Author(s):  
Frank Hohl
Keyword(s):  
Gravitational Field ◽  
Body Problem ◽  
Stellar Dynamics ◽  
Coulomb Force ◽  
Stellar Systems ◽  
Inhomogeneous Systems ◽  
Consistent Field ◽  
Self Consistent ◽  
Self Consistent Field ◽  
Simultaneous Influence

Many problems in stellar dynamics involve phenomena occurring in inhomogeneous systems in which the interaction between the particles is fully described by a self-consistent field operating in phase space. Because the particles interact by means of the long-range Coulomb force, each particle is under the simultaneous influence of a large number of other particles. Therefore, stellar systems will respond to any perturbation in a collective manner, and a study of such systems is concerned essentially with the N-body problem.

Self-Consistent Models of Disk Galaxies

1967 ◽  
Vol 150 ◽  
pp. 787 ◽  
Author(s):  
E. W. Ng
Keyword(s):  
Disk Galaxies ◽  
Self Consistent

scholarly journals A secularly evolved model for the Milky Way bar and bulge

2012 ◽  
Vol 10 (H16) ◽  
pp. 351-351 ◽  
Author(s):  
Inma Martinez-Valpuesta ◽  
Ortwin Gerhard
Keyword(s):  
Milky Way ◽  
Momentum Transport ◽  
Disk Galaxies ◽  
Kinematic Data ◽  
Angular Momentum Transport ◽  
Secular Evolution ◽  
Upper Limit ◽  
Self Consistent ◽  
The Galaxy ◽  
Pattern Speed

AbstractBars are strong drivers of secular evolution in disk galaxies. Bars themselves can evolve secularly through angular momentum transport, producing different boxy/peanut and X-shaped bulges. Our Milky Way is an example of a barred galaxy with a boxy bulge. We present a self-consistent N-body simulation of a barred galaxy which matches remarkably well the structure of the inner Milky Way deduced from star counts. In particular, features taken as signatures of a second “long bar“ can be explained by the interaction between the bar and the spiral arms of the galaxy (Martinez-Valpuesta & Gerhard 2011). Furthermore the structural change in the bulge inside l = 4° measured recently from VVV data can be explained by the high-density near-axisymmetric part of the inner boxy bulge (Gerhard & Martinez-Valpuesta 2012). We also compare this model with kinematic data from recent spectroscopic surveys. We use a modified version of the NMAGIC code (de Lorenzi et al. 2007) to study the properties of the Milky Way bar, obtaining an upper limit for the pattern speed of ~ 42 km/sec/kpc. See Fig. 1 for a comparison of one of our best models with BRAVA data (Kunder et al. 2012).

scholarly journals Towards a Self-consistent Model of a Galaxy

1987 ◽  
Vol 127 ◽  
pp. 509-510
Author(s):  
W.J.L.V. Durodie ◽  
F.D. Kahn
Keyword(s):  
Stellar Dynamics ◽  
Time Development ◽  
Symmetric Model ◽  
Spherically Symmetric ◽  
Stellar Orbits ◽  
Consistent Model ◽  
Galactic System ◽  
Self Consistent ◽  
Functional Distribution ◽  
Fundamental Equations

Using a theoretical model for the functional distribution of stars in phase space in a spherically symmetric galactic system, it is found upon solving the fundamental equations of stellar dynamics that the rotation curves produced by the model are flat for large distances within the system. the properties of the stellar orbits within such systems are investigated and an N-ring axially and equatorially symmetric model for simulating its dynamics is presented. Poisson's equation is solved by expanding density and potential in Legendre polynomials (c.f. van Albada and van Gorkom, 1977). It is helped to follow the time development of such a system under various forces.

scholarly journals Stellar Dynamics of Needles

1987 ◽  
Vol 127 ◽  
pp. 493-494
Author(s):  
Scott Tremaine ◽  
Tim de Zeeuw
Keyword(s):  
Distribution Function ◽  
Stellar Dynamics ◽  
Stellar Systems ◽  
One Dimensional ◽  
Density Distributions ◽  
Universal Distribution ◽  
Self Consistent ◽  
Triaxial Stellar Systems ◽  
Limiting Case

One dimensional “needles” are a limiting case of general triaxial stellar systems. Self-consistent, finite needles can have arbitrary longitudinal density distributions but have a fixed, universal distribution function. All needles are stable to all longitudinal perturbations but neutral to transverse perturbations.

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