Testing the cosmic distance duality relation using model-independent approach

TL;DR

This study tests the cosmic distance duality relation across various redshifts using a model-independent, flexible cosmography approach with multiple observational datasets, finding no significant deviations unless certain priors are imposed.

Contribution

It introduces a novel, model-independent method using Padé-(2,1) expansion to test CDDR at any redshift without data extrapolation, combining diverse observational data.

Findings

No significant deviations from CDDR in the range 0 to 1 with combined datasets.

Potential CDDR violation at 3-5 sigma when imposing a Gaussian prior on $M_B$.

Method effectively constrains cosmography parameters without data reconstruction.

Abstract

In this work, we test the cosmic distance duality relation (CDDR) using the arbitrary redshift pivot Pad\'e-(2,1) expansion methodology developed in arXiv:2509.16196. This approach allows us to constrain cosmography parameters and test CDDR at any redshift. Further, it does not rely on data reconstructions or extrapolations of the cosmography parameters to higher redshifts. We employ observational data from the Dark Energy Spectroscopic Instrument (DESI) Baryon Acoustic Oscillation dataset, cosmic chronometers (CC), and Type Ia supernovae from the Pantheon Plus (PP) and Dark Energy Survey Year 5 (DESY5) compilations. We find no significant deviations from the standard CDDR relation in the range $0\lesssim z \lesssim 1$ when considering DESI$+r_d$ dataset in combination with PP$+$CC and DESY5$+$CC datasets. However, on imposing a Gaussian prior on $M_B \in \mathcal{N}(-19.253, 0.027)$ (instead of treating it as a free parameter) in the dataset combination PP$+$CC, we find CDDR violation at a level of $(3-5)\sigma.$