1999/06/30 by Kenji Tomita · 9 citations
Physics and Astronomy · #Advanced Mathematical Theories and Applications #Anisotropy #Cosmology #Cosmology and Gravitation Theories #Galaxies: Formation, Evolution, Phenomena #Gravitational lens #Homogeneous #Observer (physics) #Redshift #Strong gravitational lensing #Void (composites) #astro-ph
paper · pdf · doi:10.1086/308277
published as Astrophys.J.529:38,2000 · 14 pages, 11 postscript figures Equation numbers were corrected, Apj 529(2000) No.1 in press
arxiv created 1999/12/13 · openalex publication_date 2000/01/20 · arxiv updated 2009/12/01 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/05
We study the distances and gravitational lensing in spherically symmetric inhomogeneous cosmological models consisting of inner and outer homogeneous regions that are connected by a single shell or double shells at redshift z 1 ~ 0.067. The density and Hubble parameters in the inner region are assumed to be smaller and larger, respectively, than those in the outer region. It is found that at the stage z 1 < z < 1.5 the distances from an observer in the inner voidlike region are larger than the counterparts (with equal z ) in the corresponding homogeneous Friedmann models, and hence the magnitudes for the sources at this stage are larger. This effect of the voidlike low-density region may explain the deviations of the observed (magnitude-redshift) relation of supernovae (SNe) Ia from the relation in homogeneous models, independently of the cosmological constant. When the position of the observer deviates from the center, moreover, it is shown that the distances are anisotropic, and the images of remote sources are systematically deformed. The above relation at z ≳ 1.0, and this anisotropy will observationally distinguish the role of the above voidlike region from that of the positive cosmological constant. The influence on the time delay measurement is also discussed.