A Comprehensive Analysis of Fermi Gamma-Ray Burst Data. IV. Spectral Lag and its Relation to E-p Evolution
A Comprehensive Analysis of Fermi Gamma-Ray Burst Data. IV. Spectral Lag and its Relation to E-p Evolution
复制标题
费米伽马射线爆发数据的综合分析。
DOI：
10.3847/1538-4357/aada16
复制
发表时间：
2018
影响因子：
4.9
通讯作者：
Zhang Bing
中科院分区：
文献类型：
--
作者：
Lu Rui-Jing;Liang Yun-Feng;Lin Da-Bin;Lu Jing;Wang Xiang-Gao;Lu Hou-Jun;Liu Hong-Bang;Liang En-Wei;Zhang Bing
研究了费米伽玛暴监测器（GBM）望远镜观测到的84个伽玛暴中的92个亮脉冲的光谱演化和光谱滞后行为。这些脉冲可以分为硬到软脉冲（H2S; 64/92）、H2S主导的跟踪脉冲（21/92）和其他跟踪脉冲（7/92）。我们重点研究了H2S和H2S主导的跟踪脉冲的光谱演化和光谱滞后之间的关系。光谱演化的主要趋势（滞后行为）用（）估计，其中Ep是辐射光谱中的峰值光子能量，t + t0是相对于脉冲开始-t0的观察者时间，是能量为E的光子相对于能带8-25 keV的光谱滞后。对于H2S和H2S主导的跟踪脉冲，发现和kE之间的弱相关性，其中W是脉冲宽度。我们还研究了30个波形良好的脉冲的光谱滞后行为与脉冲的峰值时间，估计光谱滞后行为的主要趋势。发现它与kE相关。我们进行模拟下的光谱演化的唯象模型，并发现这些相关性再现。然后，我们得出结论，光谱滞后密切相关的脉冲内的光谱演化。对这些观测结果最自然的解释是，发射来自同一流体单元中的电子，发射点远离中心引擎，正如在适度高-σ流出中引起磁耗散的模型中所预期的那样。
The spectral evolution and spectral lag behavior of 92 bright pulses from 84 gamma-ray bursts observed by the Fermi Gamma-ray Burst Monitor (GBM) telescope are studied. These pulses can be classified into hard-to-soft pulses (H2S; 64/92), H2S-dominated-tracking pulses (21/92), and other tracking pulses (7/92). We focus on the relationship between spectral evolution and spectral lags of H2S and H2S-dominated-tracking pulses. The main trend of spectral evolution (lag behavior) is estimated with ( ), where Ep is the peak photon energy in the radiation spectrum, t + t0 is the observer time relative to the beginning of pulse −t0, and is the spectral lag of photons with energy E with respect to the energy band 8–25 keV. For H2S and H2S-dominated-tracking pulses, a weak correlation between and kE is found, where W is the pulse width. We also study the spectral lag behavior with peak time of pulses for 30 well-shaped pulses and estimate the main trend of the spectral lag behavior with . It is found that is correlated with kE. We perform simulations under a phenomenological model of spectral evolution, and find that these correlations are reproduced. We then conclude that spectral lags are closely related to spectral evolution within the pulse. The most natural explanation of these observations is that the emission is from the electrons in the same fluid unit at an emission site moving away from the central engine, as expected in the models invoking magnetic dissipation in a moderately high-σ outflow.