Determine whether the luminosity–decay correlation evolves with redshift

Determine whether the luminosity–decay correlation for regular long gamma-ray bursts physically evolves with redshift, rather than the reduced robustness observed at high redshift being caused solely by the Malmquist-bias truncation of the luminosity distribution.

Background

The highest-redshift regular long gamma-ray burst subsample shows the weakest and least robust correlation, with larger uncertainties and a steeper fitted slope. The paper demonstrates that restricting lower-redshift samples to similarly high luminosities reproduces much of this loss of robustness, supporting a selection-effect explanation.

However, the analysis does not exclude genuine physical evolution of the correlation with redshift. The authors state that observations of fainter high-redshift bursts with more sensitive instruments would be needed to resolve this alternative.

References

However, we cannot rule out that it may instead be due to the correlation physically evolving with redshift.

— The intrinsic luminosity-decay correlation in subsamples of GRB X-ray afterglows  (2608.19332 - Shilling et al., 19 Aug 2026) in Section 3.5.4, “Redshift selection effect”; Appendix, “The cause of the correlation changing at high redshift”