Gamma-ray burst overview

Since its launch on 20 November 2004, the Swift mission has detected ~100 gamma-ray bursts (GRBs) each year, and immediately (within ~90 s) started x-ray and UV/optical observations of the afterglow. It has already collected an impressive database including prompt emission to higher sensitivities than BATSE, uniform monitoring of afterglows and rapid follow-up by other observatories notified through the GCN. The x-ray afterglows have been found to have complex temporal shapes including tail emission from the prompt phase and bright flares. X-ray and optical afterglow detections from short bursts have led to accurate localizations. It is found that short bursts can occur in non-star forming galaxies or regions, whereas long GRBs are strongly concentrated within star forming regions. The location of short bursts in regions of galaxies where late-type stars reside is consistent with the NS merger model. Concerning the connection of GRBs to supernovae, GRB 060218 associated with SN 2006aj adds a valuable member to the class of GRBs with detected supernova. The prospects for future progress are excellent given the >10 years orbital lifetime of the Swift satellite.