Spectral and timing properties of a dissipative γ-ray burst photosphere
Spectral and timing properties of a dissipative γ-ray burst photosphere
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DOI：
10.1051/0004-6361:20066739
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发表时间：
2006-11
影响因子：
6.5
通讯作者：
D. Giannios;H. Spruit
中科院分区：
文献类型：
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作者：
D. Giannios;H. Spruit
我们探讨了观测外观的光球的超相对论流与内部耗散的能量预测的磁重联模型。以前对光球区辐射传输的研究表明，能量的逐渐耗散导致光球区的热。在那里，逆康普顿散射的热辐射平流与流导致强大的光球发射光谱特性接近所观察到的即时伽玛射线暴发射。在这里，我们建立在该研究的基础上，通过计算大范围的流动特性的光谱。给出了一个精确的拟合公式，它提供了光球光谱能量分布在~10 keV到~10 MeV的能量范围内（在中央发动机框架内）作为流动的基本物理参数的函数。它有助于直接比较模型预测与观测，包括光变曲线的变化特性。我们验证了该模型自然占所观察到的聚集在E $\cdot$ $f（E）$谱的峰值能量。在这个模型中，阿马蒂关系表明最明亮的爆发倾向于每个重子具有更多的能量。如果这种趋势也适用于单个伽玛射线暴脉冲，该模型预测观察到的脉冲宽度随着光子能量的增加而变窄。
We explore the observational appearance of the photosphere of an ultrarelativistic flow with internal dissipation of energy as predicted by the magnetic reconnection model. Previous study of the radiative transfer in the photospheric region has shown that gradual dissipation of energy results in a hot photosphere. There, inverse Compton scattering of the thermal radiation advected with the flow leads to powerful photospheric emission with spectral properties close to those of the observed prompt GRB emission. Here, we build on that study by calculating the spectra for a large range of the characteristics of the flow. An accurate fitting formula is given that provides the photospheric spectral energy distribution in the ~10 keV to ~10 MeV energy range (in the central engine frame) as a function of the basic physical parameters of the flow. It facilitates the direct comparison of the model predictions with observations, including the variability properties of the lightcurves. We verify that the model naturally accounts for the observed clustering in peak energies of the E $\cdot$ $f(E)$ spectrum. In this model, the Amati relation indicates a tendency for the most luminous bursts to have more energy per baryon. If this tendency also holds for individual GRB pulses, the model predicts the observed narrowing of the width of pulses with increasing photon energy.