Speaker
Dr
J. Michael Burgess
(KTH Royal Institute of Technology)
Description
The prompt emission of the long, smooth, and single-pulsed gamma-ray
burst, GRB 141028A, is analyzed under the guise of an
external shock model. First, we fit the gamma-ray spectrum with a
two-component photon model, namely synchrotron+blackbody, and then
fit the recovered evolution of the synchrotron vFv peak to an
analytic model derived considering the emission of a relativistic
blast-wave expanding into an external medium. The prediction of the
model for the vFv peak evolution matches well with the
observations. We observe the blast-wave transitioning into the
deceleration phase. Further we assume the expansion of the
blast-wave to be nearly adiabatic, motivated by the low magnetic
field deduced from the observations. This allows us to recover
within an order of magnitude the flux density at the vFv peak,
which is remarkable considering the simplicity of the analytic
model. Under this scenario we argue that the distinction between
*prompt* and *afterglow* emission is superfluous as
both early and late time emission emanate from the same source.
While the external shock model is clearly not a universal solution,
this analysis opens the possibility that at least some fraction of
GRBs can be explained with an external shock origin of their prompt
phase.
Primary author
Dr
J. Michael Burgess
(KTH Royal Institute of Technology)
Co-author
Dr
Damien Bèguè
(KTH Royal Institute of Technology)
