Models of voids in the expanding universe

Bonnor, W. B.; Chamorro, A.

doi:10.1086/169162

Cited by 27 publications

(37 citation statements)

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“…Solving the two parts of (2.6) for t(R, r) and writing it out for each of (t 1 , R 1 ) and 2 For examples where this is not the case, see the papers by Einstein & Straus [12,13] with M min = 0 & R min = 0, and by Bonnor & Chamorro [14] where M = 0 from R = 0 to R min . Also "necks" are the (t 2 , R 2 ) leads to:…”

Section: Hyperbolic Regionsmentioning

confidence: 99%

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Structure formation in the Lemaître-Tolman model

2001

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Structure formation within the Lemaître-Tolman model is investigated in a general manner. We seek models such that the initial density perturbation within a homogeneous background has a smaller mass than the structure into which it will develop, and the perturbation then accretes more mass during evolution. This is a generalisation of the approach taken by Bonnor in 1956. It is proved that any two spherically symmetric density profiles specified on any two constant time slices can be joined by a Lemaître-Tolman evolution, and exact implicit formulae for the arbitrary functions that determine the resulting L-T model are obtained. Examples of the process are investigated numerically.

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Section: Hyperbolic Regionsmentioning

confidence: 99%

“…The solution of ψ A (x) = 0 is 14) and so x A is a good initial value for the numerical program that will find a solution of ψ H (x) = 0 by bisecting the segment [0, x A ] and checking the sign of ψ H (x A /2).…”

Section: Hyperbolic Regionsmentioning

confidence: 99%

Structure formation in the Lemaître-Tolman model

2001

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“…The physical significance of this can be viewed from diametrically opposite positions. One extreme is to regard a shell crossing singularity as unphysical and try to exclude it by assuming special initial conditions, as was the strategy in the work of Bonnor and Chamorro (Bonnor and Chamorro 1990;Chamorro 1991). However, this leads to difficulties with adjusting the model to observational data.…”

Section: Local Voidmentioning

confidence: 99%

Cosmological Observations in a Local Void

Moffat¹,

Tatarski²

1995

ApJ

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A local void in the globally Friedmann-Robertson-Walker (FRW) cosmological model is studied. The inhomogeneity is described using the Lema\^{\i}tre-Tolman-Bondi (LTB) solution with the spherically symmetric matter distribution based on the faint galaxies number counts. We investigate the effects this has on the measurement of the Hubble constant and the redshift--luminosity distance relation for moderately and very distant objects ($z \approx 0.1$ and more). The results, while fully compatible with cosmological observations, indicate that if we happened to live in such a void, but insisted on interpreting cosmological observations through the FRW model, we could get a few unexpected results. For example the Hubble constant measurement could give results depending on the separation of the source and the observer.Comment: 22 pages, 10 figures, LaTeX [aaspp,subeqn]{article}, UTPT-94-1

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“…However for larger cavities it should be more appropriate to consider their embedding in an expanding Lemaître-Friedmann-Robertson-Walker spacetime (for the specific case of void modeling in expanding universes see [24,25] and references therein).…”

Section: Introductionmentioning

confidence: 99%

Dynamical instability and the expansion-free condition

2012

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We study the dynamical instability of a spherically symmetric anisotropic fluid which collapses adiabatically under the condition of vanishing expansion scalar. The Newtonian and post Newtonian regimes are considered in detail. It is shown that within those two approximations the adiabatic index $\Gamma_1$, measuring the fluid stiffness, does not play any role. Instead, the range of instability is determined by the anisotropy of the fluid pressures and the radial profile of the energy density, independently of its stiffness, in a way which is fully consistent with results previously obtained from the study on the Tolman mass.Comment: 12 pages Revtex. Some changes in the text to match the version accepted in Gen. Rel. Gra

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Models of voids in the expanding universe

Cited by 27 publications

References 0 publications

Structure formation in the Lemaître-Tolman model

Structure formation in the Lemaître-Tolman model

Cosmological Observations in a Local Void

Dynamical instability and the expansion-free condition

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