Title: Observational aspects of an inhomogeneous cosmology
Abstract: Department of Astrophysics, University of ViennaE-mail:[email protected] of the biggest mysteries in cosmology is Dark Energy, which is required to explain theaccelerated expansion of the universe within the standard model. But maybe one can explain theobservations without introducing new physics, by simply taking one step back and re-examiningone of the basic concepts of cosmology, homogeneity. In standard cosmology, it is assumedthat the universe is homogeneous, but this is not true at small scales (<200 Mpc). Since generalrelativity, which is the basis of modern cosmology, is a non-linear theory, one can expect somebackreactions in the case of an inhomogeneous matter distribution. Estimates of the magnitudeof these backreactions (feedback) range from insignificant to being perfectly able to explain theaccelerated expansion of the universe. In the end, the only way to be sure is to test predictions ofinhomogeneous cosmological theories, such as timescape cosmology, against observational data.If these theories provide a valid description of the universe, one expects aside other effects, thatthere is a dependenceof the Hubble parameteron the line of sight matter distribution. The redshiftof a galaxy, which is located at a certain distance, is expected to be smaller if the environmentin the line of sight is mainly high density (clusters), rather than mainly low density environment(voids). Here we present a test for this prediction using redshifts and fundamental plane distancesof elliptical galaxies obtained from SDSS DR8 data. In order to get solid statistics, which canhandle the uncertainties in the distance estimate and the natural scatter due to peculiar motions,one has to systematically study a very large number of galaxies. Therefore, the SDSS forms aperfect basis for testing timescape cosmology and similar theories. The preliminary results of thiscosmological test are shown in this contribution.VIII International Workshop on the Dark Side of the Universe,June 10-15, 2012Rio de Janeiro, Brazil
Publication Year: 2012
Publication Date: 2012-01-01
Language: en
Type: article
Access and Citation
AI Researcher Chatbot
Get quick answers to your questions about the article from our AI researcher chatbot