Cosmological-model-independent tests of cosmic distance duality relation with Type Ia supernovae and radio quasars

TL;DR

This paper tests the cosmic distance duality relation (CDDR) using the latest supernovae and quasar data with model-independent methods, finding improved precision and potential hints of new physics or opacity sources in the universe.

Contribution

It introduces a refined, model-independent approach to test CDDR with larger datasets, enhancing constraints and exploring deviations that could indicate new physics or opacity effects.

Findings

Improved constraints on CDDR parameters using latest data.

Larger datasets lead to more stringent bounds on deviations.

Results suggest possible unaccounted opacity or new physics in the universe.

Abstract

In this paper, we investigate the possible deviations of the cosmic distance duality relation (CDDR) using the combination of the largest SNe Ia (Pantheon) and compact radio quasar (QSO) samples through two model-independent approaches. The deviation of CDDR is written as $D_L(z)/D_A(z)(1+z)^{-2}=\eta(z)$ and $\eta(z)=e^{\tau(z)/2}$, with the parameterizations of $F_1$ ($\tau(z) = 2\epsilon_1 z$) and $F_2$ ($\tau(z) = (1+z)^{2\epsilon_2}-1$). Furthermore, in order to compare the two resulting distances, two cosmological-model-independent methods, i.e., the nearby SNe Ia method and the GP method are employed to match the two distinct data at the same redshift. Our findings indicate that, compared with the results obtained in the literature, there is an improvement in precision when the latest SNe Ia and QSO samples are used. Specially, in the framework of nearby SNe Ia method, the CDDR would be constrained at the precision of $\Delta\epsilon_{1} = 0.013$ in Model $F_1$ and $\Delta\epsilon_{2}=0.018$ in Model $F_2$. Regarding the GP method, one observes that a larger data size would produce more stringent constraints on the CDDR parameters. Therefore, accompanied by further developments in cosmological observations and the analysis methods, our analysis provides an insight into the evidence for unaccounted opacity sources at an earlier stage of the universe, or at the very least the new physics involved.