Accelerating expansion or inhomogeneity? II. Mimicking acceleration with the energy function in the Lemaitre-Tolman model

作者：Krasinski Andrzej^*

来源：Physical Review D - Particles, Fields, Gravitation and Cosmology, 2014, 90(2): 023524.

DOI：10.1103/PhysRevD.90.023524

This is a continuation of the paper published in Phys. Rev. D 89, 023520 (2014). Here we investigate how the luminosity distance-redshift relation D-L(z) of the Lambda CDM model is duplicated in the Lemaitre-Tolman (L-T) model with Lambda = 0, constant bang-time function t(B) and the energy function E(r) mimicking accelerated expansion on the observer's past light cone (r is a uniquely defined comoving radial coordinate). Numerical experiments show that E > 0 necessarily. The functions z(r) and E(r) are numerically calculated from the initial point at the observer's position, then backward from the initial point at the apparent horizon (AH). Reconciling the results of the two calculations allows one to determine the values of E/r(2) at r = 0 and at the AH. The problems connected with continuing the calculation through the AH are discussed in detail and solved. Then z(r) and E(r) are continued beyond the AH, up to the numerical crash that signals the contact of the light cone with the big bang. Similarly, the light cone of the L-T model is calculated by proceeding from the two initial points, and compared with the Lambda CDM light cone. The model constructed here contains shell crossings, but they can be removed by matching the L-T region to a Friedmann background, without causing any conflict with the type Ia supernovae observations. The mechanism of imitating the accelerated expansion by the E(r) function is explained in a descriptive way.

• 出版日期2014-7-16