Cosmology with Gamma-Ray Bursts Using k-correction
  In the case of Gamma-Ray Bursts with measured redshift, we can calculate the k-correction to get the fluence and energy that were actually produced in the comoving system of the GRB. To achieve this we have to use well-fitted parameters of a GRB spectrum, available in the GCN database. The output of the calculations is the comoving isotropic energy E_iso, but this is not the endpoint: this data can be useful for estimating the {\Omega}M parameter of the Universe and for making a GRB Hubble diagram using Amati's relation. 
Andras Kovacs, Zsolt Bagoly, Lajos G. Balazs, Istvan Horvath, Peter   Veres
astro-ph.HE