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arXiv · 1104.0394

Gamma-ray bursts from magnetized collisionally-heated jets

Indrek Vurm·Andrei M. Beloborodov·Juri Poutanen
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Abstract

Jets producing gamma-ray bursts (GRBs) are likely to carry a neutron component that drifts with respect to the proton component. The neutron-proton collisions strongly heat the jet and generate electron-positron pairs. We investigate radiation produced by this heating using a new numerical code. Our results confirm the recent claim that collisional heating generates the observed Band-type spectrum of GRBs. We extend the model to study the effects of magnetic fields on the emitted spectrum. We find that the spectrum peak remains near 1 MeV for the entire range of the magnetization parameter $0<\epsilon_B<2$ that is explored in our simulations. The low-energy part of the spectrum softens with increasing $\epsilon_B$, and a visible soft excess appears in the keV band. The high-energy part of the spectrum extends well above the GeV range and can contribute to the prompt emission observed by Fermi/LAT. Overall, the radiation spectrum created by the collisional mechanism appears to agree with observations, with no fine-tuning of parameters.

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Indrek Vurm, Andrei M. Beloborodov, Juri Poutanen. 2011-04-03. Gamma-ray bursts from magnetized collisionally-heated jets. https://doi.org/10.1088/0004-637x/738/1/77

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