In light of the recent finding of the narrow clustering of the
geometrically-corrected gamma-ray energies emitted by Gamma Ray Bursts (GRBs),
we investigate the possibility to use these sources as standard candles to
probe cosmological parameters such as the matter density Omega_m and the
cosmological constant energy density Omega_Lambda. By simulating different
samples of gamma-ray bursts, based on recent observational results, we find
that Omega_m (with the prior Omega_m + Omega_Lambda = 1) can be determined with
accuracy ~7% with data from 300 GRBs, provided a local calibration of the
standard candles be achieved.Comment: 4 pages, 2 figures, to appear in the Proceedings of the Conference
"30 Years of GRB Discovery", Santa Fe, New Mexico, USA, September 8-12, 200
