Stability of rotating spherical stellar systems

Meza, Andrés

doi:10.1051/0004-6361:20021268

Cited by 18 publications

(21 citation statements)

References 35 publications

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“…Ellipticity can be due to rotation (e.g. ω Cen; Meylan & Mayor 1986) but also to velocity anisotropy (Stephens et al 2006;Hénon 1973), and rotating clusters can be spherical (Lynden-Bell 1960;Meza 2002). Marginal evidence for rotation was found for the young (few 100 Myr) Galactic cluster GLIMPSE-C01 with an amplitude of V rot sin i /σ 1D 0.2 (Davies et al 2011).…”

Section: Introductionmentioning

confidence: 99%

The VLT-FLAMES Tarantula Survey

Hénault-Brunet

Gieles

Evans

et al. 2012

A&A

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Although it has important ramifications for both the formation of star clusters and their subsequent dynamical evolution, rotation remains a largely unexplored characteristic of young star clusters (few Myr). Using multi-epoch spectroscopic data of the inner regions of 30 Doradus in the Large Magellanic Cloud obtained as part of the VLT-FLAMES Tarantula Survey, we search for rotation of the young massive cluster R136. From the radial velocities of 36 apparently single O-type stars within a projected radius of 10 pc from the centre of the cluster, we find evidence, at the 95% confidence level, for rotation of the cluster as a whole. We use a maximum likelihood method to fit simple rotation curves to our data and find a typical rotational velocity of ∼3 km s −1 . When compared to the low velocity dispersion of R136, our result suggests that star clusters may form with at least ∼20% of the kinetic energy in rotation.

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Section: Introductionmentioning

confidence: 99%

The VLT-FLAMES Tarantula Survey

Hénault-Brunet

Gieles

Evans

et al. 2012

A&A

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“…We have not dealt with the stability of our models in details in our paper. Although it is difficult to determine the stability domain in the parameter space of the halo model, the study of stability of the stellar system and dark matter halo is very important and some works have already been done 38,39,40,41 . To be more realistic, a more complicated case, the axisymmetric model should be considered 42,43,44,45 .…”

Section: Discussionmentioning

confidence: 99%

Distribution Function of Dark Matter With Constant Anisotropy

2008

Int. J. Mod. Phys. D

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N-body simulations of dark matter halos show that the density is cusped near the center of the halo. The density profile behaves as r −γ in the inner parts, where γ ≃ 1 for the NFW model and γ ≃ 1.5 for the Moore's model, but in the outer parts, both models agree with each other in the asymptotic behavior of the density profile. The simulations also show the information about anisotropy parameter β(r) of velocity distribution. β ≈ 0 in the inner part and β ≈ 0.5 (radially anisotropic) in the outer part of the halo. We provide some distribution functions F (E, L) with the constant anisotropy parameter β for the two spherical models of dark matter halos: a new generalized NFW model and a generalized Moore model. There are two parameters α and ǫ for those two generalized models to determine the asymptotic behavior of the density profile. In this paper, we concentrate on the situation of β(r) = 1/2 from the viewpoint of the simulation.

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“…This effect will cause the bar to increase in both size and strength. To measure the non‐radial stability of the systems we fitted the shape of an ellipsoidal mass distribution by means of an iterative procedure (Dubinski & Carlberg 1991; Katz 1991; Meza & Zamorano 1997; Meza 2002) at every half‐mass dynamical time. This detects any bar feature that is located within a given radius.…”

Section: Methodsmentioning

confidence: 99%

Radial-orbit instability of a family of anisotropic Hernquist models with and without a supermassive black hole

Buyle

Hese

Rijcke

et al. 2007

Monthly Notices of the Royal Astronomical Society

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We present a method to investigate the non-radial stability of a spherical anisotropic system that hosts a central supermassive black hole (SBH). Such systems have never been tested before for stability, although high anisotropies have been considered in the dynamical models that were used to estimate the masses of the central putative SBHs. A family of analytical anisotropic spherical Hernquist models with and without a black hole were investigated by means of N-body simulations. A clear trend emerges that the SBH has a significant effect on the overall stability of the system, that is, an SBH with a mass of a few per cent of the total mass of the galaxy can prevent or reduce the bar instabilities in anisotropic systems. Its mass determines not only the strength of the instability reduction, but also the time in which this occurs. These effects are most significant for models with strong radial anisotropies. Furthermore, our analysis shows that unstable systems with similar SBHs but with different anisotropy radii evolve differently: highly radial systems become oblate, while more isotropic models tend to form into prolate structures. In addition to this study, we also present a Monte Carlo algorithm to generate particles in spherical anisotropic systems.

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Stability of rotating spherical stellar systems

Cited by 18 publications

References 35 publications

The VLT-FLAMES Tarantula Survey

The VLT-FLAMES Tarantula Survey

Distribution Function of Dark Matter With Constant Anisotropy

Radial-orbit instability of a family of anisotropic Hernquist models with and without a supermassive black hole

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