X-ray flares in the early swift observations of the possible naked burst GRB 050421

O. Godet, K. L. Page, M. R. Goad, A. P. Beardmore, P. T. O'Brien, J. P. Osborne, D. N. Burrows, M. Capalbi, J. Kennea, V. Mangano, A. Moretti, D. Morris

Research output: Chapter in Book/Report/Conference proceedingConference contribution


We present the Swift observations of the faint burst GRB 050421. The X-ray light-curve shows two flares: the first flare peaking at ∼ 110 s after the BAT trigger (T0) and the second one peaking at ∼154 s. We argue that the mechanism producing these flares is probably late internal shocks. The X-ray light-curve shows a rapid decline with a temporal index α ∼ 3.1. The X-ray source disappears completely less than 1 hour after the trigger. An X-ray spectral softening is also observed with time from β ∼ 0.1 to ∼ 1.2. A good joint fit to the BAT and XRT spectra indicates that the early X-ray and Gamma-ray emissions are produced by the same mechanism. The X-ray spectral softening is likely due to a shift down to lower energies of the peak of the prompt emission, and the rapid decline of the X-ray emission is probably the tail of the prompt emission. This suggests that the X-ray emission is completely dominated by high latitude radiation and the external shock, if any, is below the detection threshold.

Original languageEnglish (US)
Title of host publicationX-ray Universe 2005
Number of pages2
StatePublished - 2006
EventX-ray Universe 2005 - Madrid, Spain
Duration: Sep 26 2005Sep 30 2005

Publication series

NameEuropean Space Agency, (Special Publication) ESA SP
ISSN (Print)0379-6566


OtherX-ray Universe 2005

All Science Journal Classification (ASJC) codes

  • Aerospace Engineering
  • Space and Planetary Science


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