Cosmography by GRBs: Gamma Ray Bursts as possible distance indicators

A new method to constrain the cosmological equation of state is proposed by using combined samples of gammaray bursts (GRBs) and supernovae (SNeIa). The Chevallier-Polarski-Linder parameterization is adopted for the equation of state in order to find out a realistic approach to achieve the deceleration/acceleration transition phase of dark energy models. As results, we find that GRBs, calibrated by SNeIa, could be, at least, good distance indicators capable of discriminating cosmological models with respect to ΛCDM at high redshift.