Calibration of Luminosity Correlations of Gamma-Ray Bursts Using Quasars

In order to test the efficacy of gamma-ray bursts (GRBs) as cosmological probes, we characterize the scatter in the correlations between six pairs of GRB observables. However, some of these observables depend on the luminosity distance, for which one needs to assume an underlying cosmological model. In order to circumvent this circularity problem, we use X-ray and UV fluxes of quasars as distance anchors to calculate the luminosity distance in a model-independent manner, which, in turn, is used to calculate the GRB-related quantities. We find that all six pairs of regression relations show high intrinsic scatter for both low- and high-redshift samples. This implies that these GRB observables cannot be used as model-independent high-precision cosmological probes.