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Self-organized criticality in multi-pulse gamma-ray bursts
Frontiers of Physics ( IF 6.5 ) Pub Date : 2020-10-07 , DOI: 10.1007/s11467-020-0989-x
Fen Lyu , Ya-Ping Li , Shu-Jin Hou , Jun-Jie Wei , Jin-Jun Geng , Xue-Feng Wu

The variability in multi-pulse gamma-ray bursts (GRBs) may help to reveal the mechanism of underlying processes from the central engine. To investigate whether the self-organized criticality (SOC) phenomena exist in the prompt phase of GRBs, we statistically study the properties of GRBs with more than 3 pulses in each burst by fitting the distributions of several observed physical variables with a Markov Chain Monte Carlo approach, including the isotropic energy Eiso, the duration time T, and the peak count rate P of each pulse. Our sample consists of 454 pulses in 93 GRBs observed by the CGRO/BATSE satellite. The best-fitting values and uncertainties for these power-law indices of the differential frequency distributions are: \(\alpha_E^d=1.54\pm0.09, \alpha_T^d=1.82\pm_{0.15}^{+0.14}\;and\;\alpha_P^d=2.09_{-019}^{+0.18}\), while the power-law indices in the cumulative frequency distributions are: \(\alpha_E^c=1.44_{-0.10}^{+0.08}, \alpha_T^c=1.75_-{0.13}^{+0.141}\;and\;\alpha_P^c=1.99_{-019}^{+0.16}\). We find that these distributions are roughly consistent with the physical framework of a Fractal-Diffusive, Self-Organized Criticality (FD-SOC) system with the spatial dimension S = 3 and the classical diffusion β=1. Our results support that the jet responsible for the GRBs should be magnetically dominated and magnetic instabilities (e.g., kink model, or tearing-model instability) lead the GRB emission region into the SOC state.



中文翻译:

多脉冲伽马射线暴中的自组织临界

多脉冲伽马射线暴(GRB)的可变性可能有助于从中央引擎揭示潜在过程的机制。要研究GRB的快速阶段是否存在自组织临界(SOC)现象,我们通过用马尔可夫链蒙特卡洛拟合一些观察到的物理变量的分布,统计地研究每个突发中具有3个以上脉冲的GRB的特性。包括各向同性能量E iso,持续时间T和每个脉冲的峰值计数率P。我们的样本由CGRO / BATSE卫星观测到的93个GRB中的454个脉冲组成。这些差分频率分布的幂律指数的最佳拟合值和不确定性是:\(\ alpha_E ^ d = 1.54 \ pm0.09,\ alpha_T ^ d = 1.82 \ pm_ {0.15} ^ {+ 0.14} \;和\; \ alpha_P ^ d = 2.09 _ {-019} ^ {+ 0.18} \),而累积频率分布中的幂律指数为:\(\ alpha_E ^ c = 1.44 _ {-0.10} ^ {+ 0.08},\ alpha_T ^ c = 1.75 _- {0.13} ^ {+ 0.141 } \;和\; \ alpha_P ^ c = 1.99 _ {-019} ^ {+ 0.16} \)。我们发现这些分布与分形扩散,自组织临界度(FD-SOC)系统的空间尺寸S = 3和经典扩散β = 1的物理框架基本一致。我们的结果支持负责GRB的射流应以磁性为主,并且磁性不稳定性(例如扭结模型或撕裂模型不稳定性)会将GRB发射区带入SOC状态。

更新日期:2020-10-08
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