2007/03/31 by Nikolaos Brouzakis, Nikolaos Tetradis, Eleftheria Tzavara · 73 citations
Physics and Astronomy · #Cosmology #Cosmology and Gravitation Theories #Dark Matter and Cosmic Phenomena #Dark energy #Dispersion (optics) #Galaxies: Formation, Evolution, Phenomena #Galaxy #Gravitational lens #Length scale #Redshift #Universe #Velocity dispersion #astro-ph #gr-qc #hep-ph #hep-th
paper · pdf · doi:10.1088/1475-7516/2008/04/008
published in Journal of Cosmology and Astroparticle Physics 2008(04), 008 (Institute of Physics) · 27 pages, 9 figures, revised version to appear in JCAP, analytical estimate included, typos corrected
openalex publication_date 2008/04/07 · arxiv created 2010/02/17 · arxiv updated 2010/02/26 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/06
We consider the effect on the propagation of light of inhomogeneities with sizes of order 10 Mpc or larger. The Universe is approximated through a variation of the Swiss-cheese model. The spherical inhomogeneities are void-like, with central underdensities surrounded by compensating overdense shells. We study the propagation of light in this background, assuming that the source and the observer occupy random positions, so that each beam travels through several inhomogeneities at random angles. The distribution of luminosity distances for sources with the same redshift is asymmetric, with a peak at a value larger than the average one. The width of the distribution and the location of the maximum increase with increasing redshift and length scale of the inhomogeneities. We compute the induced dispersion and bias of cosmological parameters derived from the supernova data. They are too small to explain the perceived acceleration without dark energy, even when the length scale of the inhomogeneities is comparable to the horizon distance. Moreover, the dispersion and bias induced by gravitational lensing at the scales of galaxies or clusters of galaxies are larger by at least an order of magnitude.