Gamma-ray bursts (GRBs) are far and away the most brilliant events in the Universe. They are thought to be the "birth cry" of stellar-mass black holes and to involve ultra-relativistic jets. They may mark the moment of "first light" in the universe and trace the star formation, re-ionization, and metallicity histories of the universe. In this talk, I first give an overview of the properties of GRBs. I then describe exciting recent discoveries made by the High Energy Transient Explorer-2 and Swift missions. These include (1) decisive confirmation of the connection between GRBs and core collapse supernovae, (2) new insights into the nature of "optically dark" GRBs, (3) determination of the properties and the progenitors of the recently discovered class of bursts called "X-ray Flashes," (4) solution to the mystery of short GRBs, and (5) discovery of a burst at z = 6.29 -- the first very high redshift GRB. Finally, I discuss the scientific promise of GRBs for constraining the properties of dark energy and as probes of the early universe.

ANL Physics Division Colloquium Schedule