We discuss the new surprising observational results that indicate quite convincingly that the prompt emission of gamma-ray bursts (GRBs) is due to synchrotron radiation produced by a particle distribution that has a low-energy cut-off. The evidence of this is provided by the low-energy part of the spectrum of the prompt emission, which shows the characteristic Fνα ν1/3 shape followed by Fνα ν-1/2 up to the peak frequency. This implies that although the emitting particles are in fast cooling, they do not cool completely. This poses a severe challenge to the basic ideas about how and where the emission is produced, because the incomplete cooling requires a small value of the magnetic field to limit synchrotron cooling, and a large emitting region to limit the self-Compton cooling, even considering Klein-Nishina scattering effects. Some new and fundamental ingredient is required for understanding the GRBs prompt emission. We propose proton-synchrotron as a promising mechanism to solve the incomplete cooling puzzle.

Proton-synchrotron as the radiation mechanism of the prompt emission of gamma-ray bursts? / Ghisellini, G.; Ghirlanda, G.; Oganesyan, G.; Ascenzi, S.; Nava, L.; Celotti, A.; Salafia, O. S.; Ravasio, M. E.; Ronchi, M.. - In: ASTRONOMY & ASTROPHYSICS. - ISSN 0004-6361. - 636:(2020), pp. 1-7. [10.1051/0004-6361/201937244]

Proton-synchrotron as the radiation mechanism of the prompt emission of gamma-ray bursts?

Oganesyan G.;Celotti A.;
2020-01-01

Abstract

We discuss the new surprising observational results that indicate quite convincingly that the prompt emission of gamma-ray bursts (GRBs) is due to synchrotron radiation produced by a particle distribution that has a low-energy cut-off. The evidence of this is provided by the low-energy part of the spectrum of the prompt emission, which shows the characteristic Fνα ν1/3 shape followed by Fνα ν-1/2 up to the peak frequency. This implies that although the emitting particles are in fast cooling, they do not cool completely. This poses a severe challenge to the basic ideas about how and where the emission is produced, because the incomplete cooling requires a small value of the magnetic field to limit synchrotron cooling, and a large emitting region to limit the self-Compton cooling, even considering Klein-Nishina scattering effects. Some new and fundamental ingredient is required for understanding the GRBs prompt emission. We propose proton-synchrotron as a promising mechanism to solve the incomplete cooling puzzle.
636
1
7
A82
Ghisellini, G.; Ghirlanda, G.; Oganesyan, G.; Ascenzi, S.; Nava, L.; Celotti, A.; Salafia, O. S.; Ravasio, M. E.; Ronchi, M.
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/20.500.11767/117104
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