scholarly journals The Influence of Velocity Dispersion on Dynamical Friction in Stellar Discs

1996 ◽  
Vol 169 ◽  
pp. 515-516
Author(s):  
Mattias Wahde ◽  
Karl Johan Donner ◽  
Björn Sundelius
Keyword(s):  
Numerical Simulations ◽  
Circular Orbit ◽  
Velocity Dispersion ◽  
Point Mass ◽  
Dynamical Friction ◽  
Disc Galaxy ◽  
Moderate Amount ◽  
Physical Picture ◽  
Self Gravity

We have investigated the force of dynamical friction on a softened point mass orbiting inside a disc galaxy on a planar circular orbit both analytically and by means of numerical simulations. Including a velocity dispersion large enough to stabilise the disc markedly changes the physical picture of the mechanisms producing friction, whereas the numerical value of the friction is almost unaffected. Self-gravity of the disc enhances the friction only by a moderate amount.

scholarly journals Dynamical Friction in Disk Galaxies: The Radial Dependence

1996 ◽  
Vol 157 ◽  
pp. 372-374
Author(s):  
Mattias Wahde ◽  
Karl Johan Donner
Keyword(s):  
Numerical Simulations ◽  
Decay Time ◽  
Circular Orbit ◽  
Simple Formula ◽  
Radial Dependence ◽  
Disk Galaxies ◽  
Dynamical Friction ◽  
Satellite Galaxy ◽  
Parent Galaxy ◽  
Good Agreement

AbstractA simple formula is derived for the force of dynamical friction acting on a satellite galaxy which is moving on a nearly circular orbit around its parent galaxy. Using this formula, estimates of the decay time are computed. The results are then compared with the corresponding results from numerical simulations, and are found to be in good agreement.

scholarly journals 11.15. The effect of a central massive black hole on the gas fueling

1998 ◽  
Vol 184 ◽  
pp. 485-486
Author(s):  
H. Fukuda ◽  
A. Habe ◽  
K. Wada
Keyword(s):  
Black Hole ◽  
Numerical Simulations ◽  
Gravitational Potential ◽  
Galactic Center ◽  
The Self ◽  
Massive Black Hole ◽  
Nuclear Regions ◽  
Self Gravity ◽  
Lindblad Resonance ◽  
Inner Lindblad Resonance

Nuclear activities in galaxies, such as nuclear starbursts or AGNs, are supposed to be induced by gas fueling into nuclear regions of galaxies. Non-axisymmetric gravitational potential caused by a stellar bar is a convincing mechanism for triggering gas fueling (Phinney 1994). However, numerical simulations have shown that the bar can not force the gas to accrete toward the galactic center beyond the inner Lindblad resonance (ILR). As a mechanism to overcome the ILR barrier, the double barred structure (Friedli & Martinet 1993), or the self-gravity of gas (Wada & Habe 1992, 1995; Elmegreen 1994) are proposed.

scholarly journals Neutral Hydrogen in the Magellanic Clouds

1999 ◽  
Vol 190 ◽  
pp. 37-44
Author(s):  
L. Staveley-Smith ◽  
S. Kim ◽  
S. Stanimirović
Keyword(s):  
Atomic Hydrogen ◽  
Large Scale ◽  
Milky Way ◽  
Velocity Dispersion ◽  
Neutral Hydrogen ◽  
Distribution Functions ◽  
Magellanic Clouds ◽  
Self Gravity ◽  
Rotational Shear ◽  
Compact Array

We review observations of neutral atomic hydrogen (HI) in the Magellanic Clouds (MCs). Being the nearest gas-rich neighbours of the Milky Way the MCs give us an excellent opportunity to study in detail the structure and evolution of the interstellar medium (ISM) and the effect of interactions between galaxies. HI in emission provides a probe of the structure and velocity field of the Clouds, allowing the study of their velocity dispersion, 3-D structure, and large-scale total-mass distribution. Recent data from Australia Telescope Compact Array surveys reveal a morphology (for both Clouds) which is heavily dominated by the effects of local star-formation, rotational shear, fragmentation, self-gravity and turbulence. The new data, which has a spatial resolution down to 10 pc, also allows the study of the distribution functions in velocity and mass for HI clouds. We discuss the morphology, dynamics and giant shell population of the LMC and SMC.

scholarly journals Galactic bar resonances inferred from kinematically hot stars in Gaia EDR3

2021 ◽  
Vol 508 (1) ◽  
pp. 728-736
Author(s):  
Daisuke Kawata ◽  
Junichi Baba ◽  
Jason A S Hunt ◽  
Ralph Schönrich ◽  
Ioana Ciucă ◽  
...  
Keyword(s):  
Numerical Simulation ◽  
Angular Momentum ◽  
Numerical Simulations ◽  
Momentum Distribution ◽  
Action Space ◽  
Space Distribution ◽  
Local Perturbation ◽  
Disc Galaxy ◽  
Hot Stars ◽  
Pattern Speeds

ABSTRACT Using a numerical simulation of an isolated barred disc galaxy, we first demonstrate that the resonances of the inner bar structure induce more prominent features in the action space distribution for the kinematically hotter stars, which are less sensitive to the local perturbation, such as the transient spiral arms. Then, we analyse the action distribution for the kinematically hotter stars selected from the Gaia EDR3 data as the stars with higher values of radial and vertical actions. We find several resonance features, including two new features, in the angular momentum distribution similar to what are seen in our numerical simulations. We show that the bar pattern speeds of about Ωbar ∼ 34 and 42 km s−1 kpc−1 explain all these features equally well. The resonance features we find correspond to the inner 4:1, co-rotation (CR), outer 4:1, outer Lindblad, and outer 4:3 (CR, outer 4:1, outer Lindblad, outer 4:3, and outer 1:1) resonances, when Ωbar ∼ 34 (42) km s−1 kpc−1 is assumed.

scholarly journals Numerical simulations of central stellar velocity dispersion drops in disc galaxies

2003 ◽  
Vol 409 (2) ◽  
pp. 469-477 ◽  
Author(s):  
H. Wozniak ◽  
F. Combes ◽  
E. Emsellem ◽  
D. Friedli
Keyword(s):  
Numerical Simulations ◽  
Velocity Dispersion ◽  
Stellar Velocity ◽  
Disc Galaxies

scholarly journals Stationary Orbits of Satellites of Disk Galaxies

1990 ◽  
Vol 124 ◽  
pp. 705-710
Author(s):  
Valerij L. Polyachenko
Keyword(s):  
Circular Orbit ◽  
Physical Parameters ◽  
Disk Galaxies ◽  
Dynamical Friction ◽  
Disk Radius ◽  
Friction Forces ◽  
Wide Range

AbstractThe satellite of an S-galaxy will experience opposing dynamical-friction forces from the stars of the disk and the halo. If these forces are in balance, the satellite may travel in a stable, near-circular orbit whose radius, for a wide range of physical parameters, should be limited to a zone 1.2 to 1.4 times the disk radius, much as is observed.

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