A test of Amati relation using HII galaxy distances

TL;DR

This study tests the Amati relation for Gamma-ray Bursts using model-independent HII galaxy distances and neural network interpolation, finding it unsuitable for precision cosmology due to large intrinsic scatter.

Contribution

It introduces a novel approach using HII galaxy distances and neural networks to evaluate the Amati relation without circularity issues.

Findings

Best-fit Amati parameters are consistent within 1σ.

Intrinsic scatter is large, around 28-35%.

Amati relation with HII galaxies is not suitable for precision cosmology.

Abstract

We use model-independent luminosity distances of 186 HII galaxy observations to address the circularity problem in the Amati relation for Gamma-ray Bursts (GRBs). For this purpose, we used Artificial Neural Network based interpolation to reconstruct the luminosity distance corresponding to the GRB redshift. We then use two independent GRB datasets to test the robustness of the Amati relation at redshifts below $z=2.6$. Our best-fit Amati relation parameters are consistent for the same datasets to within $1\sigma$. The intrinsic scatters which we obtain for the two datasets of about 28\% and 35\%, are comparatively larger. This implies that the Amati relation using HII galaxies as distance anchors cannot be used as a probe of precision cosmology.