Orbital characteristics of dynamical models of elliptical galaxies

1986 ◽  
Vol 39 (1) ◽  
pp. 85-102 ◽  
Author(s):  
N. Caranicolas ◽  
Ch. Vozikis
Keyword(s):  
Elliptical Galaxies ◽  
Dynamical Models

scholarly journals A simple two-component description of mass segregation for anisotropic globular clusters

2019 ◽  
Vol 14 (S351) ◽  
pp. 528-531
Author(s):  
S. Torniamenti ◽  
G. Bertin ◽  
P. Bianchini
Keyword(s):  
Numerical Simulations ◽  
Globular Clusters ◽  
Elliptical Galaxies ◽  
Dynamical Models ◽  
Two Component ◽  
Partial Energy ◽  
Energy Equipartition ◽  
Mass Segregation ◽  
The One ◽  
Component Models

AbstractAs a result of the slow action of two-body encounters, globular clusters develop mass segregation and attain a condition of only partial energy equipartition even in their central, most relaxed regions. Realistic numerical simulations show that, during the process, a radially-biased anisotropy profile slowly builds up, mimicking that resulting from incomplete violent relaxation. Commonly used dynamical models, such as the one-component King models, cannot describe these properties. Here we show that simple two-component models based on a distribution function originally conceived to describe elliptical galaxies, recently truncated and adapted to the context of globular clusters, can describe in detail what is observed in complex and realistic numerical simulations.

scholarly journals Planetary Nebulae in elliptical galaxies: Dynamical models for Centaurus A

1997 ◽  
Vol 180 ◽  
pp. 472-472
Author(s):  
Anne Mathieu ◽  
Herwig Dejonghe
Keyword(s):  
Elliptical Galaxy ◽  
Planetary Nebulae ◽  
Elliptical Galaxies ◽  
Minor Axis ◽  
Dynamical Models ◽  
Dust Lane ◽  
Centaurus A

We use planetary nebulae major- and minor-axis kinematics (Hui et al. 1995) of the dust-lane elliptical galaxy NGC 5128 (Centaurus A) to build triaxial dynamical models.

scholarly journals Dynamical Models of Elliptical Galaxies

1975 ◽  
Vol 69 ◽  
pp. 207-208
Author(s):  
C. P. Wilson
Keyword(s):  
Elliptical Galaxies ◽  
Dynamical Models ◽  
Self Consistent

Self-consistent dynamical models of elliptical galaxies have been constructed using a modification of the Prendergast-Tomer algorithm. They reproduce many of the observed properties of elliptical galaxies.

scholarly journals Elliptical Galaxies: Darkly Cloaked or Scantily Clad?

2004 ◽  
Vol 220 ◽  
pp. 165-170
Author(s):  
A. J. Romanowsky ◽  
N. G. Douglas ◽  
K. Kuijken ◽  
M. R. Merrifield ◽  
M. Arnaboldi ◽  
...  
Keyword(s):  
Galaxy Formation ◽  
Velocity Dispersion ◽  
Elliptical Galaxies ◽  
Small Sample ◽  
Early Type ◽  
Dynamical Models ◽  
Show Evidence ◽  
Major Merger ◽  
Nearby Galaxies ◽  
Ab Initio Models

Planetary nebulae (PNe) may be the most promising tracers in the halos of early-type galaxies. We have used multi-object spectrographs on the WHT and the VLT, and the new Planetary Nebula Spectrograph on the WHT, to obtain hundreds of PN velocities in a small sample of nearby galaxies. These ellipticals show weak halo rotation, which may be consistent with ab initio models of galaxy formation, but not with more detailed major merger simulations. the galaxies near L* show evidence of a universal declining velocity dispersion profile, and dynamical models indicate the presence of little dark matter within 5 Reff—implying halos either not as massive or not as centrally concentrated as CDM predicts.

scholarly journals Dynamical Models for Axisymmetric and Triaxial Galaxies

1987 ◽  
Vol 127 ◽  
pp. 271-290
Author(s):  
Tim de Zeeuw
Keyword(s):  
Elliptical Galaxies ◽  
Disk Galaxies ◽  
Dynamical Models ◽  
Figure Rotation ◽  
Considerable Insight

Non–spherical dynamical models for galaxies, and the methods for their construction, are reviewed. The theory for two–integral axisymmetric models is reasonably well developed. Stäckel models give considerable insight in the structure of both three–integral axisymmetric models and non–rotating triaxial systems. Triaxial galaxies with appreciable figure rotation require much further study. Applications to elliptical galaxies and the bulges of disk galaxies are discussed.

scholarly journals The outer haloes of massive, elliptical galaxies

2009 ◽  
Vol 5 (H15) ◽  
pp. 92-92
Author(s):  
Payel Das ◽  
Ortwin Gerhard ◽  
Flavio de Lorenzi ◽  
Emily McNeil ◽  
Eugene Churazov ◽  
...  
Keyword(s):  
Dark Matter ◽  
Parametric Method ◽  
Elliptical Galaxies ◽  
Matter Content ◽  
Likelihood Method ◽  
Orbital Structure ◽  
Dynamical Models ◽  
X Ray ◽  
Mass Distributions ◽  
Velocity Dispersions

The outer haloes of massive elliptical galaxies are dark-matter dominated regions where stellar orbits have longer dynamical timescales than the central regions and therefore better preserve their formation history. Dynamical models out to large radii suffer from a degeneracy between mass and orbital structure, as the outer kinematics are unable to resolve higher moments of the line-of-sight velocity distribution. We mitigate this degeneracy for a sample of quiescent, massive, nearby ellipticals by determining their mass distributions independently using a non-parametric method on X-ray observations of the surrounding hot interstellar medium. We then create dynamical models using photometric and kinematic constraints consisting of integral-eld, long-slit and planetary nebulae (PNe) data extending to ~50 kpc. The rst two galaxies of our sample, NGC 5846 and NGC 1399, were found to have very shallow pro jected light distributions with a power law index of ~1.5 and a dark matter content of 70–80% at 50 kpc. Spherical Jeans models of the data show that, in the outer haloes of both galaxies, the pro jected velocity dispersions are almost inde- pendent of the anisotropy and that the PNe prefer the lower end of the range of mass distributions consistent with the X-ray data. Using the N-body code NMAGIC, we cre- ated axisymmetric models of NGC 5846 using the individual PNe radial velocities in a likelihood method and found them to be more constraining than the binned velocity dispersions. Characterising the orbital structure in terms of spherically averaged proles of the velocity dispersions we nd σψ > σr > σθ.

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