Cosmology with Gamma-Ray Bursts
  Gamma-Ray Bursts (GRBs) are the brightest sources in the universe, emit
mostly in the hard X-ray energy band and have been detected at redshifts up to
~8.1. Thus, they are in principle very powerful probes for cosmology. I shortly
review the researches aimed to use GRBs for the measurement of cosmological
parameters, which are mainly based on the correlation between spectral peak
photon energy and total radiated energy or luminosity. In particular, based on
an enriched sample of 95 GRBs, I will provide an update of the analysis by
Amati et al. (2008) aimed at extracting information on Omega_M and, to a less
extent, on Omega_Lambda, from the Ep,i - Eiso correlation. I also briefly
discuss the perspectives of using GRBs as cosmological beacons for high
resolution absorption spectroscopy of the IGM (e.g., WHIM), and as tracers of
the SFR, up to the "dark ages" (z > 6) of the universe.
