Deciphering the Ancient Universe with Gamma-Ray Bursts

Gamma-ray bursts (GRBs) are the most luminous and violent explosions detectable out to the edge of the observable Universe. As soon as their cosmological origin was established, it became apparent that GRBs can serve as powerful probes of the high-redshift Universe. The association of long GRBs with the deaths of massive stars imply that they trace the sites and history of massive star formation. Their optical and near-infrared afterglows reveal spectral imprints of their environments, including the interstellar medium of their host galaxies as well as the intergalactic medium during cosmic reionization. With the Swift Observatory in orbit, such expectations are now being materialized. With GRB 050904, we found that the Universe was already largely ionized at z=6.3. The discovery of GRB 090423 at z~8.2, the most distant astrophysical object known to date, clearly demonstrates that in the coming years, GRBs will offer us an unprecedented view into the mysterious era of cosmic reionization and the formation of the first stars and galaxies. And yet, our knowledge concerning the GRBs themselves remain appallingly meager, such as their progenitors, their true energetics, the mechanisms of jet formation, particle acceleration and prompt emission, etc. The aim of this conference is to discuss the latest observational and theoretical developments in this exciting field of GRBs, with a strong emphasis on their use as probes of the high redshift universe. Non-GRB studies of the high redshift Universe, involving e.g. supernovae, galaxies, quasars and background radiation, are also essential elements of this conference.