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Title: Light propagation and the distance-redshift relation in a realistic inhomogeneous universe

Journal Article · · Physical Review (Section) D: Particles and Fields; (USA)
 [1];  [2]
  1. Department of Physics, Faculty of Science, Hirosaki University, Hirosaki 036, Japan (JP)
  2. NASA/Fermilab Astrophysics Center, Fermi National Accelerator Laboratory, Batavia, Illinois 60510 Research Institute for Theoretical Physics, Hiroshima University, Takehara, Hiroshima 725, Japan

We investigate the propagation of light rays in a clumpy universe constructed by a cosmological version of the post-Newtonian approximation. We show that the linear approximation to the propagation equations is valid in the region {ital z}{approx lt}1 even if the density contrast is much larger than unity. Based on a general order-of-magnitude statistical consideration, we argue that the linear approximation is still valid for {ital z}{approx gt}1. Then we give a general formula for the distance-redshift relation in a clumpy universe and derive an explicit expression for a simplified situation in which the effect of the gravitational potential of inhomogeneities dominates. In the light of the derived relation we discuss the validity of the Dyer-Roeder distance. Furthermore, we consider a simple model of an inhomogeneous universe and investigate statistical properties of light rays. We find that the result of this specific example also supports the validity of the linear approximation.

OSTI ID:
5250540
Journal Information:
Physical Review (Section) D: Particles and Fields; (USA), Vol. 40:8; ISSN 0556-2821
Country of Publication:
United States
Language:
English