X-Ray Plateaus in Gamma-Ray Burst Afterglows and Their Application in Cosmology

Abstract

Abstract For gamma-ray bursts (GRBs) with a plateau phase in the X-ray afterglow, a so-called L–T–E correlation that tightly connects the isotropic energy of the prompt GRB (E γ,iso) with the end time of the X-ray plateau (T a ) and the corresponding X-ray luminosity at the end time (L X) has been found. Here we show that there is a clear redshift evolution in the correlation. Furthermore, because the power-law indices of L X and E γ,iso in the correlation function are almost identical, the L–T–E correlation is insensitive to cosmological parameters and cannot be used as a satisfactory standard candle. On the other hand, based on a sample including 121 long GRBs, we establish a new three-parameter correlation that connects L X, T a , and the spectral peak energy E p, i.e., the L–T–E p correlation. This correlation strongly supports the so-called Combo-relation established by Izzo et al. After correcting for the redshift evolution, we show that the de-evolved L–T–E p correlation can be used as a standard candle. By using this correlation alone, we are able to constrain the cosmological parameters as Ω m = 0.389 − 0.141 + 0.202 (1σ) for the flat ΛCDM model, or Ω m = 0.369 − 0.191 + 0.217 and w = − 0.966 − 0.678 + 0.513 (1σ) for the flat wCDM model. Combining with other cosmological probes, more accurate constraints on the cosmology models are presented.