Godet 2007 GRB 050822的观测

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astro-ph/0702262 [abs, ps, pdf, other] :

Title: GRB 050822: Detailed analysis of an XRF observed by Swift
Authors: O. Godet, K.L. Page, J. Osborne, B. Zhang, D.N. Burrows, P.T. O'Brien, J. E. Hill, J. Racusin, A.P. Beardmore, M.R. Goad, A. Falcone, D.C. Morris, H. Ziaeepour
Comments: 26 pages (referee format), 8 figures, submitted to A&A

We report on the temporal and spectral characteristics of the early X-ray emission from the GRB 050822 as observed by Swift. This burst is likely to be an XRF showing major X-ray flares in its XRT light-curve. The quality of the data allows a detailed spectral analysis of the early afterglow in the X-ray band. During the X-ray flares, a positive correlation between the count rate and the spectral hardness (i.e. higher the count rate is and harder the spectrum is) is clearly seen for the X-ray flares. This behaviour similar to that seen for Gamma-ray pulses indicates that the energy peak of the spectrum is in the XRT energy band and it moves at lower energy with time. We show evidence for the possible detection of the emergence of the forward-shock emission produced at a radius larger than 4 x 10^{16} cm (a forming region clearly different to that producing the prompt emission). Finally, we show that the null detection of a jet break up to T_0+4 x 10^6s in the X-ray light curve of this XRF can be understood: i) if the jet seen on-axis is uniform with a large opening angle (theta > 20 deg); or ii) if the jet is a structured Gaussian-like jet with the line-of-sight outside the bright Gaussian core.