Observational Constraints on Cosmological Models with the Updated Long Gamma-Ray Bursts

TL;DR

This paper calibrates long Gamma-Ray Bursts using supernova data to create a high-redshift dataset, then constrains seven cosmological models with combined observational data, addressing the circularity problem.

Contribution

It introduces a new calibration of 109 long GRBs independent of cosmological assumptions, enabling improved constraints on cosmological models.

Findings

Successfully calibrated 59 high-redshift GRBs for cosmological use

Provided joint constraints on 7 cosmological models using multiple datasets

Demonstrated the effectiveness of GRBs in cosmological parameter estimation

Abstract

In the present work, by the help of the newly released Union2 compilation which consists of 557 Type Ia supernovae (SNIa), we calibrate 109 long Gamma-Ray Bursts (GRBs) with the well-known Amati relation, using the cosmology-independent calibration method proposed by Liang {\it et al.}. We have obtained 59 calibrated high-redshift GRBs which can be used to constrain cosmological models without the circularity problem (we call them ``Hymnium'' GRBs sample for convenience). Then, we consider the joint constraints on 7 cosmological models from the latest observational data, namely, the combination of 557 Union2 SNIa dataset, 59 calibrated Hymnium GRBs dataset (obtained in this work), the shift parameter $R$ from the WMAP 7-year data, and the distance parameter $A$ of the measurement of the baryon acoustic oscillation (BAO) peak in the distribution of SDSS luminous red galaxies. We also briefly consider the comparison of these 7 cosmological models.