Astron. Astrophys. 326, 23-28 (1997)

5. Conclusion

The pseudo-Newtonian gravitational potential appearing in the metric (1) that realistically approximates our universe, incorporating inhomogeneities in a FRW background, is related nontrivially to that density fluctuation distribution. The Green function (or kernel or propagator, in field theory terms) generally has a different spatial extent, or compactness, than the Newtonian case which corresponds to its late time, near neighborhood limit. In consequence, light propagation behavior for those regions of parameter space far from that limit differ from the Newtonian.

In the dynamical Sachs-Wolfe effect of the redshift induced by inhomogeneities along the light path, the deviation was shown to be significant but the overall magnitude too small to be observationally interesting. For the endpoint Sachs-Wolfe effect of gravitational potential fluctuations at the source, the deviation could be viewed as an effective transfer function modifying the density perturbation power spectrum, with potentially important consequences for the normalization of the primordial density spectrum and hence the predictions of that model on smaller scales as a galaxy formation scenario.

© European Southern Observatory (ESO) 1997

Online publication: April 20, 1998
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