The parameter of the dark energy equation of state for high redshifts

Ariadna Montiel-Arenas and Nora Bret\'on,

If the dark energy changes with redshift, the best plan is to measure it over a wide range of redshifts, but supernovae cannot be detected out past redshift 1.7. Gamma-ray bursts(BRBs) offer a means to extend the Hubble measurements to at least redshifts of 6. The reason is that GRBs are visible across much larger distances than supernovae. We study the behaviour of the parameter of the equation of state $w(z)$ as function of the redshift data from GRBs, to check its deviations from its most accepted value of -1.