Can Gamma-Ray Bursts Be Used to Measure Cosmology? A Further Analysis

D. Xu; Z. G. Dai; E. W. Liang

doi:10.1086/466509

paper

Can Gamma-Ray Bursts Be Used to Measure Cosmology? A Further Analysis

arXiv:astro-ph/0501458 · doi:10.1086/466509

Abstract

Three different methods of measuring cosmology with gamma-ray bursts (GRBs) have been proposed since a relation between the $γ$ -ray energy $E_{γ}$ of a GRB jet and the peak energy $E_{p}$ of the $ν F_{ν}$ spectrum in the burst frame was reported by Ghirlanda and coauthors. In Method I, to calculate the probability for a favored cosmology, only the contribution of the $E_{γ} - E_{p}$ relation that is already best fitted for this cosmology is considered. We apply this method to a sample of 17 GRBs, and obtain the mass density $Ω_{M} = 0.1 5_{- 0.13}^{+ 0.45}$ ( $1 σ$ ) for a flat $Λ$ CDM universe. In Method II, to calculate the probability for some certain cosmology, contributions of all the possible $E_{γ} - E_{p}$ relations that are best fitted for their corresponding cosmologies are taken into account. With this method, we find a constraint on the mass density $0.14 < Ω_{M} < 0.69$ ( $1 σ$ ) for a flat universe. In Method III, to obtain the probability for some cosmology, contributions of all the possible $E_{γ} - E_{p}$ relations associated with their unequal weights are considered. With this method, we obtain an inspiring constraint on the mass density $0.16 < Ω_{M} < 0.45$ ( $1 σ$ ) for a flat universe, and a $χ_{d o f}^{2} = 19.08/15 = 1.27$ for the concordance model of $Ω_{M} = 0.27$ . (abridged)

arXiv comment26 pages including 6 figures, different methods compared, accepted for publication in ApJ

Can Gamma-Ray Bursts Be Used to Measure Cosmology? A Further Analysis

Abstract

References in corpus (79)

Cited by in corpus (55)