Model‐independent Multivariable Gamma‐Ray Burst Luminosity Indicator and Its Possible Cosmological Implications

Abstract

We present a multi-variable regression analysis to several observable quantities for a sample of 15 gamma-ray bursts (GRBs). The observables used in the analysis includes the isotropic gamma-ray energy (E_{gamma,iso}), the peak energy of the nu F_nu spectrum in the rest frame (E_p'), and the rest frame break time of the optical afterglow light curves(t_b'). A strong dependence of E_{gamma, iso on E_p' and t_b' is derived. We also extend the analysis to the isotropic afterglow energies in the X-ray and the optical bands, respectively, and find that they are essentially not correlated with E_p' and t_b'. Regarding the E_{gamma, iso(E_p', t_b') relationship as a luminosity indicator, we explore the possible constraints on the cosmological parameters using the GRB sample. Our results indicate 0.13