Gamma Ray Bursts


Gamma Ray Bursts (GRBs) are the most energetic and mysterious events in the universe and potentially a powerful probe of cosmology and of the universe at high redshifts.

They shine hundreds of times brighter than a typical supernova and about a 1018 times as bright as the Sun, making them briefly the brightest source of cosmic gamma-ray photons in the observable Universe.

They consist of an in tense flash of gamma rays, lasting anywhere from a fraction of a second to up to a few minutes. This first emission (prompt)  is normally followed by a much longer and fainter signal (afterglow) emitted at longer wavelength (X-ray, UV, Optical, Infrared, microwave and radio).

In the past few years NASA has launched two high energy space observatory Swift, in December 2004 and Fermi, in June 2008. Since their launch both satellites have been making significant discoveries and contributions to many areas of high-energy astrophysics.

Even if the latest years have been characterized by important discoveries their emission mechanisms are still debatable. Therefore, important questions are still to be answered especially concerning their origin and environment as well their physics.




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