Determination of Cosmological Parameters from Gamma Ray Burst Characteristics and Afterglow Correlations

Abstract

We use the correlation relation between the energy emitted by the GRBs in their prompt phases and the X-ray afterglow fluxes, in an effort to constrain cosmological parameters and aiming to construct a Hubble diagram at high redshifts, i.e. beyond those found with Type Ia supernovae. We use a sample of 126 \textit{Swift} GRBs, that we have selected among more than 800 long bursts observed until April 2015. The selection is based on a few observational constraints: GRB flux higher than 0.4 $photons/c{m}^2/s$ in the band 15-150 keV, spectrum fitted with simple power law, redshift accurately known and given, and X-ray afterglow observed and flux measured. The statistical method of maximum likelihood is then used to determine the best cosmological parameters (${\Omega }_M$, ${\Omega }_{\Lambda }$) that give the best correlation for two relations: a) the Amati relation (between intrinsic spectral peak energy $E_{p,i}$ and the equivalent isotropic energy), b) the Dainotti relation, namely between the X-ray afterglow luminosity $L_X$ and the break time $T_a$, which is observed in the X-ray flux FX. Although the number of GRBs with high redshifts is rather small, and despite the notable dispersion found in the data, the results we have obtained are quite encouraging and promising. The results obtained using the Amati relation are close to those obtained using the Type Ia supernovae, and they appear to indicate a universe dominated by dark energy. However, those obtained with the correlation between the break time and the X-ray afterglow luminosity is consistent with the findings of the WMAP study of the cosmic microwave background radiation, and they seem to indicate a de Sitter-Einstein universe dominated by matter.

References in corpus (15)

• The Hubble Diagram to Redshift >6 from 69 Gamma-Ray Bursts
• A time - luminosity correlation for Gamma Ray Bursts in the X - rays
• Gamma-ray Burst Cosmology
• Gamma-Ray Bursts in $1.8<z<5.6$ Suggest that the Time Variation of the Dark Energy is Small
• Cosmological Evolution of Long Gamma-ray Bursts and Star Formation Rate
• The redshift distribution of gamma-ray bursts revisited
• Enhanced Cosmological GRB Rates and Implications for Cosmogenic Neutrinos
• Selection effects in Gamma Ray Bursts correlations: consequences on the ratio between GRB and star formation rates
• Accessing the population of high redshift Gamma Ray Bursts
• The low-luminosity tail of the GRB distribution: the case of GRB 980425
• Gamma-ray burst afterglow plateau break time - luminosity correlations favour thick shell models over thin shell models
• Open issues with the gamma-ray burst redshift distribution
• Revisiting the Amati and Yonetoku Correlations with Swift GRBs
• Spitzer Mid-Infrared Spectroscopy of 70um-Selected Distant Luminous Infrared Galaxies
• High-Energy Cosmology: gamma rays and neutrinos from beyond the galaxy