On testing the distance duality relation with the latest

The distance duality relation has been constrained with the latest Hubble parameter data and the type Ia supernova Union 2.1 data by employing a model independent approach. The best suitable values of the three parameters are not zero, but the distance duality relation is consistent with the observations at the 1σ confidence level. To inspect the influence of the value of Hubble constant, the dimensionless Hubble constant h has been treated as a free parameter, and the results show that the observations favor the distance duality relation at the 1σ confidence level. After the dimensionless Hubble constant h has been marginalized, the results demonstrate that the distance duality relation is consistent with the observed data at the 1σ confidence level.