Swift observations of the prompt and early afterglow emission from the bright flaring burst GRB051117A.

We report on the temporal and spectral characteristics of the early X-ray emission from the bright flaring Gamma-Ray Burst GRB051117A as observed by Swift. The superb quality of the early X-ray data allows us to study the evolution of the prompt and early afterglow emission for this GRB in unprecedented detail. A temporal spectral analysis of the early X-ray data shows that the photon index, Γ, and source intensity are highly correlated with the spectrum being significantly harder when brighter. The simplest explanation for the observed temporal behaviour is an abrupt movement of the peak of the Band-function to higher energies at the onset of each flare, followed by a slower decline to lower energies as the flare fades. We find no evidence for the presence of lines in the early X-ray spectra, with a 3σ upper limit of < 15 eV for an assumed narrow line of width of 100eV at the peak of the effective area. © 2007 American Institute of Physics [ABSTRACT FROM AUTHOR]