Gamma-ray burst data strongly favour the three-parameter fundamental plane (Dainotti) correlation over the two-parameter one

Gamma-ray bursts (GRBs), observed to redshift z = 9.4, are potential probes of the largely unexplored z similar to 2.7-9.4 part of the early Universe. Thus, finding relevant relations among GRB physical properties is crucial. We find that the Platinum GRB data compilation, with 50 long GRBs (with relatively flat plateaus and no flares) in the redshift range 0.553 <= z <= 5.0, and the LGRB95 data compilation, with 95 long GRBs in 0.297 <= z <= 9.4, as well as the 145 GRB combination of the two, strongly favour the 3D Fundamental Plane (Dainotti) correlation (between the peak prompt luminosity, the luminosity at the end of the plateau emission, and its rest-frame duration) over the 2D one (between the luminosity at the end of the plateau emission and its duration). The 3D Dainotti correlations in the three data sets are standardizable. We find that while LGRB95 data have similar to 50 per cent larger intrinsic scatter parameter values than the better-quality Platinum data, they provide somewhat tighter constraints on cosmological-model and GRB-correlation parameters, perhaps solely due to the larger number of data points, 95 versus 50. This suggests that when compiling GRB data for the purpose of constraining cosmological parameters, given the quality of current GRB data, intrinsic scatter parameter reduction must be balanced against reduced sample size.

Automated summary

Gamma-ray bursts (GRBs) are important probes of the early Universe in the largely unexplored redshift range of z ≈ 2.7-9.4. This study finds that the 3D Fundamental Plane correlation between peak luminosity, plateau luminosity, and rest-frame duration of GRBs is favored over the 2D correlation between plateau luminosity and duration. Furthermore, the larger sample size of the LGRB95 data leads to tighter constraints on cosmological and GRB-correlation parameters, despite the larger scatter of intrinsic scatter parameter values compared to the Platinum data.