Résumé
Long duration Gamma-Ray Bursts (GRBs) may serve as new standard candles toconstrain cosmological parameters by probing the Hubble diagram well beyond therange of redshift currently accessible using type-Ia supernovae. Thestandardization of GRBs is based on relations which correlate two or moreparameters, found from gamma-ray spectral modelling, of which one is stronglydependent on the cosmological model. Amati relation, in particular, is betweenthe source rest frame energy (Ei,p) at which the prompt gamma-ray spectralenergy distribution peaks and the isotropic-equivalent bolometric energy (Eiso).We have selected a sample of 23 long GRBs (LGRBs) and 2 short GRBs (SGRBs) withknown redshifts, which have been detected by the Fermi GBM and LAT instrumentsin eight years of operations, from July 2008 to December 2016. We have derivedEi,p and Eiso for these LGRBs and SGRBs using the GBM and LAT data in jointspectral fits, often requiring multiple components, thus extending thecomputation of Eiso to the GeV range. Our results show that LGRBs detected bythe Fermi-LAT with significant GeV emission are consistent with the Amatirelation. These results further enhance the possibility to use the GRBs ascosmological standard candles.