SPECTRAL AND POLARIZATION PROPERTIES OF PHOTOSPHERIC EMISSION FROM STRATIFIED JETS
SPECTRAL AND POLARIZATION PROPERTIES OF PHOTOSPHERIC EMISSION FROM STRATIFIED JETS
复制标题
DOI：
10.1088/0004-637x/789/2/159
复制
发表时间：
2014-05
期刊：
影响因子：
--
通讯作者：
Hirotaka Ito;S. Nagataki;J. Matsumoto;Shiu-Hang Lee;A. Tolstov;J. Mao;M. Dainotti;A. Mizuta
中科院分区：
文献类型：
--
作者：
Hirotaka Ito;S. Nagataki;J. Matsumoto;Shiu-Hang Lee;A. Tolstov;J. Mao;M. Dainotti;A. Mizuta
我们探讨的光谱和偏振特性的光球发射分层喷流，其中多个组件，分离的尖锐的速度剪切区域，分布在横向方向。计算了在高光学深度区域注入的热光子的传播，直到它们从光球层逃逸。研究发现，喷流内部横向结构的存在导致了光谱的非热特征和发射中明显的偏振信号。随着剪切区速度梯度的增大，偏振度和热谱的偏离度有增大的趋势。特别地，当速度剪切区在不同的横向（θ）位置上间隔很近时，多分量喷流的辐射可以再现典型的观测到的伽玛射线暴谱，而与观测者的位置无关。与发射相关联的偏振度在宽范围的观察者角度下是显著的（>几个百分比），并且可以高于30%。
We explore the spectral and polarization properties of photospheric emissions from stratified jets in which multiple components, separated by sharp velocity shear regions, are distributed in lateral directions. Propagation of thermal photons injected at a high optical depth region are calculated until they escape from the photosphere. It is found that the presence of the lateral structure within the jet leads to the nonthermal feature of the spectra and significant polarization signal in the resulting emission. The deviation from thermal spectra, as well as the polarization degree, tends to be enhanced as the velocity gradient in the shear region increases. In particular, we show that emissions from multicomponent jet can reproduce the typical observed spectra of gamma-ray bursts irrespective of the position of the observer when a velocity shear region is closely spaced in various lateral (θ) positions. The degree of polarization associated with the emission is significant (>few percent) at a wide range of observer angles and can be higher than 30%.