Low redshift calibration of the Amati relation using galaxy clusters

Abstract: In this work, we use angular diameter distances of 38 galaxy clusters with joint X-ray/SZE observation to circumvent the circularity problem in the Amati relation for Gamma-ray Bursts (GRBs). Assuming the validity of cosmic-distance duality relation, we obtain the luminosity distance from the cluster angular diameter distance and use that to calculate the isotropic equivalent energy of two different GRB datasets, after restricting the GRB redshift range to $z<0.9$. We then check the validity of the Amati relation for both these datasets. The best-fit Amati relation parameters using galaxy cluster distances as low-redshift anchors are consistent with a previous estimate for the same dataset. The intrinsic scatter which we obtain for the two datasets is about 45% and 15%, and is comparable with that found by other distance anchors used to vet the Amati relation.