Assessment of the cosmic distance duality relation using Gaussian process

Two types of distance measurement are important in cosmological observations, the angular diameter distance d(A) and the luminosity distance d(L). In this work, we carried out an assessment of the theoretical relation between these two distance measurements, namely the cosmic distance-duality relation, from type Ia supernova (SN-Ia) data, the cosmic chronometer (CC) Hubble parameter data, and baryon acoustic oscillation (BAO) data using Gaussian Process (GP). The luminosity distance curve and the angular diameter distance curve are extracted from the SN-Ia data and the combination of BAO and CC data, respectively, using the GP. The distance duality relation is checked by a non-parametric reconstruction using the reconstructed H, d(L), and the volume-averaged distance D-v. We compare the results obtained for different choices of the covariance function employed in the GP. It is observed that the theoretical distance duality relation is in well agreement with the present analysis in 2 sigma for the overlapping redshift domain 0 <= z <= 2 of the reconstruction.