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Swift observations of GRB050128: the early X-ray afterglow

S. Campana·L. A. Antonelli·G. Chincarini·S. Covino·G. Cusumano·D. Malesani·V. Mangano·A. Moretti·C. Pagani·P. Romano·G. Tagliaferri·M. Capalbi·M. Perri·P. Giommi·L. Angelini·P. Boyd·D. N. Burrows·J. E. Hill·C. Gronwall·J. A. Kennea·S. Kobayashi·P. Kumar·P. Meszaros·J. A. Nousek·P. W. A. Roming·B. Zhang·A. F. Abbey·A. P. Beardmore·A. Breeveld·M. R. Goad·O. Godet·K. O. Mason·J. P. Osborne·K. L. Page·T. Poole·N. Gehrels
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Abstract

Swift discovered GRB050128 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 with index ~ -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 behaviour as either an early jet break or evidence for a transition from the fast cooling regime to the slow cooling regime in a wind environment.

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S. Campana, L. A. Antonelli, G. Chincarini, S. Covino, G. Cusumano, D. Malesani, V. Mangano, A. Moretti, C. Pagani, P. Romano, G. Tagliaferri, M. Capalbi, M. Perri, P. Giommi, L. Angelini, P. Boyd, D. N. Burrows, J. E. Hill, C. Gronwall, J. A. Kennea, S. Kobayashi, P. Kumar, P. Meszaros, J. A. Nousek, P. W. A. Roming, B. Zhang, A. F. Abbey, A. P. Beardmore, A. Breeveld, M. R. Goad, O. Godet, K. O. Mason, J. P. Osborne, K. L. Page, T. Poole, N. Gehrels. 2005-04-14. Swift observations of GRB050128: the early X-ray afterglow. https://doi.org/10.1086/430883

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