SIMBAD references

The large scatters of luminosity relations of gamma-ray bursts (GRBs) have been one of the most important reasons preventing the extensive application of GRBs in cosmology. Many efforts have been made to seek tight luminosity relations. With the latest sample of 116 GRBs with measured redshift and spectral parameters, we investigate 6 two-dimensional (2D) correlations and 14 derived three-dimensional (3D) correlations of GRBs to explore the possibility of decreasing the intrinsic scatters of the luminosity relations of GRBs. We find the 3D correlation of E_peak-τ_RT-L to be evidently tighter (at the 2σ confidence level) than its corresponding 2D correlations, i.e., the E_peak-L and τ_RT-L correlations. In addition, the coefficients before the logarithms of E_peak and τ_RTin the E_peak-τ_RT-L correlation are almost exact opposites of each other. Inputting this situation as a prior reduces the relation to L∝(E'_peak/τ_RT')^0.842 ±0.064^, where E'_peak and τ'_RTdenote the peak energy and minimum rise time in the GRB rest frame. We discuss how our findings can be interpreted/understood in the framework of the definition of the luminosity (energy released in units of time). Our argument about the connection between the luminosity relations of GRBs and the definition of the luminosity provides a clear direction for exploring tighter luminosity relations of GRBs in the future.