2 research outputs found
Testing the cosmic distance duality with X-ray gas mass fraction and supernovae data
In this paper we discuss a new cosmological model-independent test for the
cosmic distance duality relation (CDDR), , where and are the angular
and luminosity distances, respectively. Using the general expression for X-ray
gas mass fraction () of galaxy clusters, , we show that observations jointly with type Ia
supernovae (SNe Ia) data furnish a validity test for the CDDR. To perform our
analysis we use 38 measurements recently studied by two groups
considering different assumptions to describe the clusters (La Roque {\it{et
al.}} 2006 and Ettori {\it{et al.}} 2009) and two subsamples of SNe Ia distance
luminosity extracted from the Union2 compilation. In our test we consider the
parameter as a function of the redshift parameterized by two different
functional forms. It is found that the La Roque {\it{et al.}} (2006) sample is
in perfect agreement with the duality relation () whereas the Ettori
{\it{et al.}} (2009) sample presents a significant conflict.Comment: 5 pages, 2 figures, 1 table, Letter to MNRAS (in press