Cosmological Studies with Gamma-Ray Bursts

Gamma-Ray Burst (GRB) explosions from the first generation of stars offer an exciting opportunity to probe the epoch of reionization. Clues about how and when the intergalactic medium was ionized can be read off their UV emission spectrum. Roughly a percent of all GRBs should be strongly gravitationally lensed by intervening stars. A microlensed lightcurve can be inverted to reconstruct the surface brightness profile of the GRB image on the sky, with micro-arcsecond resolution.