Campana, S.S.CampanaAntonelli, L. A.L. A.AntonelliChincarini, G.G.ChincariniCapalbi, MilviaMilviaCapalbiPerri, MatteoMatteoPerriGiommi, PaoloPaoloGiommi2020-09-172020-09-172005-05-01https://hdl.handle.net/20.500.13025/246The Astrophysical Journal, Volume 625, Issue 1, pp. L23-L26.Swift discovered GRB 050128 with the Burst Alert Telescope and promptly pointed its narrow field instruments to monitor the afterglow. X-ray observations started 108 s after the trigger time. The early decay of the afterglow is relatively flat, with a temporal decay modeled with a power-law index of ~-0.3. A steepening occurs at later times (~1500 s) with a power-law index of ~-1.3. During this transition, the observed X-ray spectrum does not change. We interpret this behavior as either an early jet break or evidence of a transition from the fast cooling regime to the slow cooling regime in a wind environment.Gamma Rays BurstsX-Rays Individual Alphanumeric GRB 05012810.1086/430883http://adsabs.harvard.edu/abs/2005ApJ...625L..23C2005ApJ...625L..23C