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arXiv 1206.3531astro-ph.HEastro-ph.CO
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同步辐射和同步辐射自康普顿光变曲线中的伽马射线暴瞬发辐射变化

Gamma Ray Burst Prompt Emission Variability in Synchrotron and Synchrotron Self-Compton Lightcurves

L. Resmi, B. Zhang

摘要:

伽马射线暴的瞬发辐射被认为起源于在高度相对论外流中加速的电子。由中央引擎喷射出的壳层之间的碰撞引起的“内部冲击”是电子加速的主要候选者。虽然同步辐射通常被用来解释内激波模型中的瞬发γ射线发射,同步辐射自康普顿(SSC)也被认为是辐射机制的一个可能的候选者。在这种情况下,人们会期望在低能量下的同步辐射分量,裸眼GRB 080319 B被认为是这样的例子。鉴于GRB 080319 B的γ光变曲线比光学GRB的γ光变曲线变化更大,本文研究了同步辐射和SSC分量之间的相对变化。我们开发了一个“自上而下”的形式主义,通过使用观测量来推断物理参数,并随后研究的同步辐射和SSC组成部分的伽玛暴的时间结构。我们补充的形式主义与“自下而上”的方法,其中同步加速器和SSC光变曲线计算通过蒙特卡罗模拟的内部冲击模型。这两种方法都得出同样的结论。同步光变曲线的微小变化在SSC光变曲线中只能适度放大。因此,SSC模型不能充分解释GRB 080319 B的伽马射线发射特性。

英文摘要:

Gamma Ray Burst prompt emission is believed to originate from electrons accelerated in a highly relativistic outflow. "Internal shocks" due to collisions between shells ejected by the central engine is a leading candidate for electron acceleration. While synchrotron radiation is generally invoked to interpret prompt gamma-ray emission within the internal shock model, synchrotron self-Compton (SSC) is also considered as a possible candidate of radiation mechanism. In this case, one would expect a synchrotron emission component at low energies, and the naked-eye GRB 080319B has been considered as such an example. In the view that the gamma-ray lightcurve of GRB 080319B is much more variable than its optical counterpart, in this paper we study the relative variability between the synchrotron and SSC components. We develop a "top-down" formalism by using observed quantities to infer physical parameters, and subsequently to study the temporal structure of synchrotron and SSC components of a GRB. We complement the formalism with a "bottom-up" approach where the synchrotron and SSC lightcurves are calculated through a Monte-Carlo simulations of the internal shock model. Both approaches lead to the same conclusion. Small variations in the synchrotron lightcurve can be only moderately amplified in the SSC lightcurve. The SSC model therefore cannot adequately interpret the gamma-ray emission properties of GRB 080319B.

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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