Cosmological-model-independent tests for the distance-duality relation from galaxy clusters and type Ia supernova

Abstract

We perform a cosmological-model-independent test for the distance-duality (DD) relation η(z) = DL (z)(1 + z)-2/DA (z), where DL and DA are the luminosity distance and angular diameter distance, respectively, with a combination of observational data for DL taken from the latest Union2 SNe Ia and that for D A provided by two galaxy cluster samples compiled by De Filippis etal. and Bonamente etal. Two parameterizations for η(z), i.e., η(z) = 1 + η0 z and η(z) = 1 + η0 z/(1 + z), are used. We find that the DD relation can be accommodated at 1σ confidence level (CL) for the De Filippis etal. sample and at 3σ CL for the Bonamente etal. sample. We also examine the DD relation by postulating two more general parameterizations: η(z) = η0 + η1 z and η(z) = η0 + η1 z/(1 + z), and find that the DD relation is compatible with the results from the De Filippis etal. and the Bonamente etal. samples at 1σ and 2σ CLs, respectively. Thus, we conclude that the DD relation is compatible with present observations. © 2011. The American Astronomical Society. All rights reserved.