Chincarini, G.G.ChincariniMangano, V.V.ManganoMoretti, A.A.MorettiPerri, MatteoMatteoPerriGiommi, PaoloPaoloGiommi2020-09-172020-09-172006-01-01https://hdl.handle.net/20.500.13025/519Proceedings of the The X-ray Universe 2005 (ESA SP-604). 26-30 September 2005, El Escorial, Madrid, Spain. Editor A. Wilson, p.871Following a brief introduction we show that the observations obtained so far with the Swift satellite begin to shed light over a variety of problems that were left open following the excellent performance and related discoveries of the Italian - Dutch Beppo SAX satellite. The XRT light curves show common characteristics that are reasonably understood within the framework of the fireball model. Unforeseen flares are however detected in a large fraction of the GRB observed and the energy emitted by the brightest ones may be as much as 85% of the total soft X ray emission measured by XRT. These characteristics seems to be common to long and short bursts.conference paperhttp://adsabs.harvard.edu/abs/2006ESASP.604..871C2006ESASP.604..871C