http://arxiv.org/abs/1402.3123
In view of interpreting the cosmological observations precisely, especially when they involve narrow light beams, it is crucial to understand how light propagates in our statistically homogeneous, clumpy, Universe. Among the various approaches to tackle this issue, Swiss-cheese models propose an inhomogeneous spacetime geometry which is an exact solution of Einstein’s equation, while the Dyer-Roeder approximation deals with inhomogeneity in an effective way. In this article, we demonstrate that both methods generate the same distance-redshift relation, at a well-controlled level of approximation. The Swiss-cheese and Dyer-Roeder approaches are therefore undistinguishable, when applied to interpretation of cosmological data. The proof relies on completely analytical arguments, and is illustrated by numerical results.
P. Fleury
Fri, 14 Feb 14
34/42
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