Large scale structure simulations of inhomogeneous Lemaître-Tolman-Bondi void models

Alonso, David; García-Bellido, J.; Haugbølle, Troels; Vicente, J. F. De

doi:10.1103/physrevd.82.123530

Cited by 40 publications

(49 citation statements)

References 47 publications

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“…Unfortunately, linear perturbation equations in the spherical void universe have not been solved [54], because the number of isometries in a spherically symmetric inhomogeneous spacetim are less than in a homogeneous and isotropic spacetime. Though some authors [55][56][57][58][59] have studied the perturbation equations using a local-Friedmann-Lemaître-Robertson-Walker (FLRW) approximation which neglects shear of the background spacetime, it is not clear how to evaluate the accuracy for the approximation. Actually, in this paper, we will show that the shear effect plays an important role in the growth of the perturbations by using another complementary analytic approach proposed in our last paper [60].…”

Section: Introductionmentioning

confidence: 99%

Two-point correlation function of density perturbations in a large void universe

2013

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We study the two-point correlation function of density perturbations in a spherically symmetric void universe model which does not employ the Copernican principle. First we solve perturbation equations in the inhomogeneous universe model and obtain density fluctuations by using a method of non-linear perturbation theory which was adopted in our previous paper. From the obtained solutions, we calculate the two-point correlation function and show that it has a local anisotropy at the off-center position differently from those in homogeneous and isotropic universes. This anisotropy is caused by the tidal force in the off-center region of the spherical void. Since no tidal force exists in homogeneous and isotropic universes, we may test the inhomogeneous universe by observing statistical distortion of the two-point galaxy correlation function. *

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Section: Introductionmentioning

confidence: 99%

Two-point correlation function of density perturbations in a large void universe

2013

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“…Clearly, structure formation places a key constraint on such models by probing their difference from the concordance model, and so serves as a test of the Copernican principle [10]. Structure formation in LTB models has only been quantified for the special case which neglects the coupling of the scalar gravitational potential to vector and tensor degrees of freedom [11,10,12,13,14,15]. While this seems reasonable, the accuracy has not been quantified.…”

Section: Introductionmentioning

confidence: 99%

Evolution of linear perturbations in spherically symmetric dust spacetimes

February¹,

Larena²,

Clarkson³

et al. 2014

Class. Quantum Grav.

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Abstract. We present results from a numerical code implementing a new method to solve the master equations describing the evolution of linear perturbations in a spherically symmetric but inhomogeneous background. This method can be used to simulate several configurations of physical interest, such as relativistic corrections to structure formation, the lensing of gravitational waves and the evolution of perturbations in a cosmological void model. This paper focuses on the latter problem, i.e. structure formation in a Hubble scale void in the linear regime. This is considerably more complicated than linear perturbations of a homogeneous and isotropic background because the inhomogeneous background leads to coupling between density perturbations and rotational modes of the spacetime geometry, as well as gravitational waves. Previous analyses of this problem ignored this coupling in the hope that the approximation does not affect the overall dynamics of structure formation in such models. We show that for a giga-parsec void, the evolution of the density contrast is well approximated by the previously studied decoupled evolution only for very large-scale modes. However, the evolution of the gravitational potentials within the void is inaccurate at more than the 10% level, and is even worse on small scales.

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“…); extra symmetries like conformal Weyl gravity [9], [10] or massive gravitons [11]; introduction of extra dimensions (like in DGP models [12], or Kaluza-Klein compactifications); new effective interactions (like the Galileon [13] field, etc. ); finally there is the possibility that the observed dimming of supernovae is not due to acceleration in a FRW universe but to large inhomogeneities from gravitational collapse, or from large LTB Voids [14][15][16][17]. For reviews on many of these interesting alternatives we refer the interested reader to Ref.…”

Section: Introductionmentioning

confidence: 99%

A new perspective on dark energy modeling via genetic algorithms

Nesseris¹,

García-Bellido²

2012

J. Cosmol. Astropart. Phys.

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118

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We use Genetic Algorithms to extract information from several cosmological probes, such as the type Ia supernovae (SnIa), the Baryon Acoustic Oscillations (BAO) and the growth rate of matter perturbations. This is done by implementing a model independent and bias-free reconstruction of the various scales and distances that characterize the data, like the luminosity dL(z) and the angular diameter distance dA(z) in the SnIa and BAO data, respectively, or the dependence with redshift of the matter density Ωm(a) in the growth rate data, f σ8(z). These quantities can then be used to reconstruct the expansion history of the Universe, and the resulting Dark Energy (DE) equation of state w(z) in the context of FRW models, or the mass radial function ΩM (r) in LTB models. In this way, the reconstruction is completely independent of our prior bias. Furthermore, we use this method to test the Etherington relation, ie the well-known relation between the luminosity and the, which is equal to 1 in metric theories of gravity. We find that the present data seem to suggest a 3-σ deviation from one at redshifts z ∼ 0.5. Finally, we present a novel way, within the Genetic Algorithm paradigm, to analytically estimate the errors on the reconstructed quantities by calculating a Path Integral over all possible functions that may contribute to the likelihood. We show that this can be done regardless of the data being correlated or uncorrelated with each other and we also explicitly demonstrate that our approach is in good agreement with other error estimation techniques like the Fisher Matrix approach and the Bootstrap Monte Carlo.

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Large scale structure simulations of inhomogeneous Lemaître-Tolman-Bondi void models

Cited by 40 publications

References 47 publications

Two-point correlation function of density perturbations in a large void universe

Two-point correlation function of density perturbations in a large void universe

Evolution of linear perturbations in spherically symmetric dust spacetimes

A new perspective on dark energy modeling via genetic algorithms

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