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arXiv 1210.7802astro-ph.HE
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费米伽马射线暴中观测到的LAT瞬发辐射的强子模型

Hadronic Models for LAT Prompt Emission Observed in Fermi Gamma-Ray Bursts

Patrick Crumley, Pawan Kumar

摘要:

本文研究了费米LAT观测到的伽马射线暴(GRB)瞬发相中强子过程产生大于100 MeV光子的可能性。我们分析计算了伽玛射线暴喷流内高能质子与γ射线相互作用产生的质子辐射和次级电子-正电子对辐射。我们考虑了光子π介子和贝特-海特勒对产生过程,以产生次级电子和正电子,然后通过逆康普顿和同步加速器过程辐射。我们也考虑质子本身的同步辐射。我们计算所需的能量在质子中产生典型的费米-LAT通量的几个microJy在100兆电子伏。对于光子介子和贝特-海特勒过程,我们发现质子所需的能量比观测到的伽马射线能量大一千倍或更多。对于质子同步加速器,质子的最小洛伦兹因子约为2 × 10 ^6。如果质子被伽玛暴中的相对论性无碰撞冲击加速,这比预期的要大得多。我们还提供了中微子通量的估计预计从光强子过程。虽然单个爆发的通量低于冰立方的探测极限,但通过将几个爆发的贡献相加,可能会排除光强子模型。因此,光强子过程似乎是一个不太可能的候选人产生的费米-LAT辐射期间的即时阶段的伽玛暴。

英文摘要:

This paper examines the possibility that hadronic processes produce the >100 MeV photons in the prompt phase of gamma-ray bursts (GRBs) observed by the Fermi-LAT. We calculate analytically the radiation from protons and from secondary electron-positron pairs produced by high energy protons interacting with gamma-rays inside of the GRB jet. We consider both photo-pion and Bethe-Heitler pair production processes to create secondary electrons and positrons that then radiate via inverse Compton and synchrotron processes. We also consider synchrotron radiation from the protons themselves. We calculate the necessary energy in protons to produce typical Fermi-LAT fluxes of a few microJy at 100 MeV. For both of the photo-pion and Bethe-Heitler processes, we find that the required energy in protons is larger than the observed gamma-ray energy by a factor of a thousand or more. For proton synchrotron, the protons have a minimum Lorentz factor ~2x10^6. This is much larger than expected if the protons are accelerated by relativistic collisionless shocks in GRBs. We also provide estimates of neutrino fluxes expected from photo-hadronic processes. Although the flux from a single burst is below IceCube detection limits, it may be possible to rule out photo-hadronic models by adding up the contribution of several bursts. Therefore, photo-hadronic processes seem an unlikely candidate for producing the Fermi-LAT radiation during the prompt phase of GRBs.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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