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arXiv · 1103.5746

Gamma-Ray Burst without Baryonic and Magnetic Load?

Kunihito Ioka·Yutaka Ohira·Norita Kawanaka·Akira Mizuta
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Abstract

We show that, contrary to common belief, internal shocks can arise in an accelerating radiation-dominated jet if it is confined even weakly to a converging opening angle because the acceleration declines. The radiation-dominated internal shock (RDIS) enables a very efficient yet highly nonthermal emission by Fermi-like photon acceleration, keeping the electron-positron ($e^{\pm}$) pair photosphere and inertia up to a high Lorentz factor >1000. In gamma-ray bursts (GRBs), a weak confinement would persist beyond the progenitor star or surrounding matter because of the fast cocoon accompanying the breakout jet. The simplest model predicts few high-energy cosmic rays and neutrinos, and a correlation between the early afterglow and the GeV-TeV prompt emission. The central engine allows a less fine-tuned baryon load than previously thought, even including pure-leptonic unmagnetized outflows.

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Kunihito Ioka, Yutaka Ohira, Norita Kawanaka, Akira Mizuta. 2011-09-14. Gamma-Ray Burst without Baryonic and Magnetic Load?. https://doi.org/10.1143/ptp.126.555

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