Spatial averaging and apparent acceleration in inhomogeneous spaces
Spatial averaging and apparent acceleration in inhomogeneous spaces
复制标题
非均匀空间中的空间平均和表观加速度
DOI：
10.1007/s10714-011-1277-4
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发表时间：
2012
影响因子：
2.8
通讯作者：
Antonio Enea Romano
中科院分区：
文献类型：
--
作者：
Y.Arai;et al.;Antonio Enea Romano
As an alternative to dark energy that explains the observed acceleration of the universe, it has been suggested that we may be at the center of an inhomogeneous isotropic universe described by a Lemaitre–Tolman–Bondi (LTB) solution of Einstein’s field equations. To test this possibility, it is necessary to solve the null geodesics. In this paper we first give a detailed derivation of a fully analytical set of differential equations for the radial null geodesics as functions of the redshift in LTB models. As an application we use these equaions to show that a positive averaged accelerationaDobtained in LTB models through spatial averaging can be incompatible with cosmological observations. We provide examples of LTB models with positiveaDwhich fail to reproduce the observed luminosity distanceDL(z). Since the apparent cosmic accelerationaFLRWis obtained from fitting the observed luminosity distance to a FLRW model we conclude that in general a positiveaDin LTB models does not imply a positiveaFLRW.
