Ellipsoidal configurations in the de Sitter spacetime

Balaguera-Antolínez, A.; Mota, David F.; Nowakowski, M.

doi:10.1088/0264-9381/23/13/013

Cited by 16 publications

(21 citation statements)

References 69 publications

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“…Clustering of DDE over scales smaller than about 100 Mpc has been the subject of a number of recent articles (Caimmi 2007;Balaguera-Antolínez et al 2006;Mainini 2005;Percival 2005;Wang 2006;Balaguera-Antolínez et al 2007). Most attention has been focussed on models in which the DDE couples to baryonic and /or dark matter, since DDE clustering is expected to be strongest in such theories (Amendola 2000;Brookfield et al 2006a;Manera & Mota 2006;Pettorino et al 2005).…”

Section: Introductionmentioning

confidence: 99%

On the Magnitude of Dark Energy Voids and Overdensities

Mota

Shaw

Silk

2008

ApJ

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We investigate the clustering of dark energy within matter overdensities and voids. In particular, we derive an analytical expression for the dark energy density perturbations, which is valid both in the linear, quasi-linear and fully non-linear regime of structure formation. We also investigate the possibility of detecting such dark energy clustering through the ISW effect. In the case of uncoupled quintessence models, if the mass of the field is of order the Hubble scale today or smaller, dark energy fluctuations are always small compared to the matter density contrast. Even when the matter perturbations enter the non-linear regime, the dark energy perturbations remain linear. We find that virialised clusters and voids correspond to local overdensities in dark energy, with $\delta_{\phi}/(1+w) \sim \Oo(10^{-5})$ for voids, $\delta_{\phi}/(1+w) \sim \Oo(10^{-4})$ for super-voids and $\delta_{\phi}/(1+w) \sim \Oo(10^{-5})$ for a typical virialised cluster. If voids with radii of $100-300 {\rm Mpc}$ exist within the visible Universe then $\delta_{\phi}$ may be as large as $10^{-3}(1+w)$. Linear overdensities of matter and super-clusters generally correspond to local voids in dark energy; for a typical super-cluster: $\delta_{\phi}/(1+w) \sim \Oo(-10^{-5})$. The approach taken in this work could be straightforwardly extended to study the clustering of more general dark energy models.Comment: 20 pages, 14 figures. Accepted by the Astrophys.

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Section: Introductionmentioning

confidence: 99%

On the Magnitude of Dark Energy Voids and Overdensities

Mota

Shaw

Silk

2008

ApJ

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“…For instance, with ρ vac = 0 only two configurations are allowed to have angular velocity along the minor axis and to be in equilibrium, namely, the Maclaurin solution (oblate) with 0 < q 3 < 1 and the Jacobi solution (triaxial) with 0 < q 3 < 0.582 where q 3 = a 3 /a 1 (the value q bif 3 = 0.582 is known as the bifurcation point). With the inclusion of ρ vac in the virial equation, we find two effects [24]. In first place, we see that the bifurcation point becomes a increasing function of ζ. Secondly, we find a second bifurcation point q bif 3(min) such that for q 3 < q bif 3(min) , the only allowed solution is again the Maclaurin solution.…”

Section: Non-spherical Configurationsmentioning

confidence: 83%

Dark Energy in an Astrophysical Context

Nowakowski¹,

Balaguera-Antolínez²

2006

AIP Conference Proceedings

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We explore local consequences of a non-zero cosmological constant on astrophysical structures. We find that the effects are not only sensitive to the density of the configurations but also to the geometry. For non-homogeneous configurations, we calculate the effects for a polytropic configurations and the isothermal sphere. Special emphasis is put on the fact that the cosmological constant sets certain scales of length, time, mass and density. Sizable effects are established for non spherical systems such as elliptical galaxy clusters where the effects of Λ are growing with the flatness of the system. The equilibrium of rotating ellipsoids is modified and the cosmological constant allows new configurations of equilibrium.

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“…Therefore, an adiabatic star with a polytropic index of 4/3 becomes unstable in the presence of DE. The dynamic stability of pure polytropic models was also investigated by Balaguera-Antolínez et al (2006, 2007, by using a static criterion of stability. Our criterion is valid for any equation of state P(ρ, T ).…”

Section: Equilibrium Solutionsmentioning

confidence: 99%

A brief analysis of self-gravitating polytropic models with a non-zero cosmological constant

Merafina

Бисноватый-Коган

Tarasov

2012

A&A

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Context. We investigate the equilibrium and stability of polytropic spheres in the presence of a non-zero cosmological constant. Aims. We solve the Newtonian gravitational equilibrium equation for a system with a polytropic equation of state of the matter P = Kρ γ introducing a non-zero cosmological constant Λ. Methods. We consider the cases of n = 1, 1.5, 3 and construct series of solutions with a fixed value of Λ. For each value of n, the non-dimensional equilibrium equation has a family of solutions, instead of the unique solution of the Lane-Emden equation at Λ = 0. Results. The equilibrium state exists only for central densities ρ 0 higher than the critical value ρ c . There are no static solutions at ρ 0 < ρ c . We investigate the stability of equilibrium solutions in the presence of a non-zero Λ and show that dark energy reduces the dynamic stability of the configuration. We apply our results to the analysis of the properties of the equilibrium states of clusters of galaxies in the present universe with non-zero Λ.

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Ellipsoidal configurations in the de Sitter spacetime

Cited by 16 publications

References 69 publications

On the Magnitude of Dark Energy Voids and Overdensities

On the Magnitude of Dark Energy Voids and Overdensities

Dark Energy in an Astrophysical Context

A brief analysis of self-gravitating polytropic models with a non-zero cosmological constant

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