2009/03/09 by Kenji Tomita, Kaiki Taro Inoue · 1 citation
Physics and Astronomy · #Cosmology and Gravitation Theories #Galaxies: Formation, Evolution, Phenomena #Gamma-ray bursts and supernovae #astro-ph.CO #astro-ph.GA
paper · pdf · doi:10.1103/physrevd.79.103505
published as Phys.Rev.D79:103505,2009 · 9 pages, 2 figures
arxiv created 2009/03/09 · openalex publication_date 2009/05/07 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
Recent observational data of supernovae point to \ensuremathΛ-dominated flat cosmological models. However, an alternative model in which we happen to live in an underdense region requires no dark energy or modification of gravity. This challenges the Copernican principle. We show that the integrated Sachs-Wolfe (ISW) effect is an excellent discriminator between anti-Copernican inhomogeneous models and the standard Copernican models. As a reference model, we consider an anti-Copernican inhomogeneous model that consists of two inner negatively curved underdense regions and an outer flat Einstein-de Sitter region. We assume that these regions are connected by two thin walls at redshifts z=0.067 and z=0.45. In the inner two regions, the first-order ISW effect is dominant and comparable to that in the concordant flat-\ensuremathΛ models. In the outer Einstein-de Sitter region, the first-order ISW effect vanishes but the second-order ISW effect plays a dominant role, while the first-order ISW effect is dominant in the flat-\ensuremathΛ models at moderate redshifts. This difference can discriminate the anti-Copernican models from the concordant flat-\ensuremathΛ model. At high redshifts, the second-order ISW effect is dominant both in our inhomogeneous model and in the concordant model. In the outer region, moreover, the ISW effect due to large-scale density perturbations with a present matter density contrast ϵm0\ensuremath≪0.37 is negligible, while the effect due to small-scale density perturbations (such as clusters of galaxies, superclusters, and voids) with ϵm0\ensuremath≫0.37 would generate anisotropies which are larger than those generated by the ISW effect in the concordant model.