Gamma-ray bursts at near-IR/optical/X-ray wavelengths

GRBs remained a puzzle for many high-energy astrophysicists since their discovery in 1967, but with the advent of X-ray satellites like BSAX, RXTE and those of the Third Interplanetary Network, it has been possible since 1997 to discover the first optical/IR counterparts just within a few hours of occurrence. This has greatly improved our understanding of these sources and the physical properties of the afterglows, revealing the existence of beaming and the different emitting regions but has also posed many new questions. The launch of Swift in Nov 2004 has opened a new era in GRB research thanks to the detection of a considerable number of events, together with other satellites like HETE-2 and INTEGRAL. The classical, long duration GRBs,have been observed to originate at cosmological distances in a range of redshifts with 0.105 <= z <= 4.50 implying energy releases of similar to 10(51) ergs. The results on GRB 021004 and GRB 030329 confirm that the central engines that power these extraordinary events are due to be collapse of massive stars rather than the merging of compact objects as previously also suggested. Short GRBs still remain a mystery in spite of the recent detection of the first X-ray afterglow for one such event.