Are long gamma-ray bursts standard candles?

Understand

Gamma-ray bursts (GRBs) are widely proposed as an effective probe to trace the Hubble diagram of the Universe in high redshift range.

• However, the calibration of GRBs is not as easy as that of type-Ia supernovae (SNe Ia).
• Most calibrating methods at present make use one or some of the empirical luminosity correlations, e.g., Amati relation.
• One of the underlying assumptions of these calibrating methods is that the empirical correlation is universal over all redshifts.