The radiative processes responsible for the GRBs and their afterglows
Dimitrios Giannios (Purdue ) - March 17, 2014 at 12:10 pm
The radiative mechanisms behind the gamma-ray-burst (GRB) emission remain
hotly debated. For quite some time, synchrotron emission from
ultra-relativistic electrons has been considered as a promising model for the
prompt GRB. Despite intensive study, the serious problems of the
model remain. They include the lack of explanation for the observed
clustering of the peak of the spectrum at ~1MeV, the sharpness of
the peak and the spectral slope below the peak.
I will describe, instead, how the radiation from the
photosphere of the jet not only accounts for the observed peak energy
but also for the overall GRB spectrum if one allows for energy to be
injected to electrons around the location of the Thomson photosphere. The
resulting spectrum is shaped by Compton scattering rather
independently of the details of the dissipation process and the jet composition.
At the last part of the talk, I focus on the GRB afterglows and
discuss how we can use radio afterglow observations years after the burst to study
particle acceleration at subrelativistic shocks.
The seminar will be held in B-1 Hearst Field Annex.
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