Testing the cosmic distance duality relation using Type Ia supernovae and radio quasars through model-independent methods*

Abstract In this study, we perform a cosmological-model-independent test on the cosmic distance duality relation (CDDR) by comparing the angular diameter distance (ADD) obtained from the compact radio quasars (QSOs) with the luminosity distance (LD) obtained from the Pantheon+ Type Ia supernovae (SNIa) sample. The binning method and artificial neural network are employed to match ADD data with LD data at the same redshift, and three different parameterizations are adopted to quantify possible deviations from the CDDR. We initially investigate the effects of specific prior values for the absolute magnitude from SNIa and linear size scaling factor l from QSOs on the CDDR test. The results demonstrate that these prior values introduce significant biases in the CDDR test. To avoid the biases, we propose a method independent of and l to test the CDDR, which treats the fiducial value of a new variable as a nuisance parameter and then marginalize its impact with a flat prior in the statistical analysis. The results show that the CDDR is consistent with the observational data, and QSOs can serve as a powerful tool for testing the CDDR independent of cosmological models.