Ioka 2007 伽玛暴瞬时辐射的机制－－质子加速

主要内容:
在光球层内，热的正负电子对被质子加速成幂律分布，产生非热的辐射谱。

精彩摘抄:


文章信息:

arXiv:0708.1249 [ps, pdf, other]

Title: Unstable GRB photospheres and electron-positron annihilation lines

Authors: Kunihito Ioka, Kohta Murase, Kenji Toma, Shigehiro Nagataki, Takashi Nakamura

Comments: 4 pages, 2 figures

Subjects: Astrophysics (astro-ph)

We propose an emission mechanism of prompt gamma-ray bursts (GRBs) that can reproduce the observed non-thermal spectra with high radiative efficiencies, >50%. Internal dissipation below a photosphere can create a radiation-dominated thermal fireball. If electron-positron pairs outnumber protons, radiative acceleration of pairs drives the two-stream instabilities between pairs and protons, leading to the ``proton sedimentation'' in the accelerating pair frame. Pairs are continuously shock heated by proton clumps, scattering the thermal photons into the broken power-law shape, with the non-thermal energy that is comparable to the proton kinetic energy, consistent with observations. Pair photospheres become unstable around the radius of the progenitor star where strong thermalization occurs, if parameters satisfy the observed spectral (Yonetoku) relation. Pair annihilation lines are predicted above continua, which could be verified by GLAST.