论文标题
在结构化喷气场景下，短伽马射线爆发的光度分布
The Luminosity Distribution of Short Gamma-Ray Bursts under a Structured Jet Scenario
论文作者
论文摘要
GRB 170817a的发光度远低于其他SGRB的亮度。无线电余辉发射的静光运动的测量证实了相对论射流的存在，并且结构化射流模型可以很好地解释发射特征。 In this paper, we calculate the luminosity distribution of sGRBs and its evolution with redshift based on the structured (Gaussian) jet model, and find that the typical luminosity increase with redshift, for nearby sGRBs (such as for luminosity distance less than 200 Mpc) the typical gamma-ray luminosity is just around 10^47-10^48 erg s-1, which naturally explains the very low radiation luminosity of GRB 170817a。我们通过Fermi-GBM得出了SGRB的检测概率，发现SGRB的预期检测率仅在数百MPC的距离内约1 YR-1。我们探索了合并时间分布对观察到的特征的幂律指数α的影响，并发现它对观察到的光度和观察角分布几乎没有影响。但是，非常有趣的是，对于不同的α值，观察到的SGRB数量的分布非常不同，因此可以通过观察到的SGRB数量分布来确定α的值。我们使用贝叶斯方法进行定量分析，并发现当观察到的已知红移的SGRB数量超过200个以上时，可以识别α的值。最后，我们比较了我们与已知红移的SGRBS的伽马射线发光度分布的结果，并发现我们的结果与我们的仿真结果相处良好，这意味着我们的结果是一致的。
Luminosity of GRB 170817A is much lower than that of other sGRBs. The measurement of the superluminal movement of the radio afterglow emission confirms the presence of the relativistic jet, and the emission features can be well explained by the structured jet model. In this paper, we calculate the luminosity distribution of sGRBs and its evolution with redshift based on the structured (Gaussian) jet model, and find that the typical luminosity increase with redshift, for nearby sGRBs (such as for luminosity distance less than 200 Mpc) the typical gamma-ray luminosity is just around 10^47-10^48 erg s-1, which naturally explains the very low radiation luminosity of GRB 170817A. We derived the detection probability of sGRBs by Fermi-GBM and found that the expected detection rate of sGRBs is only about 1 yr-1 within the distance of several hundred Mpc. We explored the effect of the power-law index α of the merger time distribution on the observed characteristics and found that it had little effect on the observed luminosity and viewing-angle distributions. However, it is very interesting that, for different values of α, the distributions of the number of observed sGRBs are quite different, so it is possible to determine the value of α through observed distributions of the number of sGRBs. We used the Bayesian method to make a quantitative analysis and found that the value of α may be identified when the number of observed sGRBs with known redshifts is more than 200. Finally, we compare our results of gamma-ray luminosity distribution with sGRBs with known redshifts, and found that our results are consistent with the observation, which implies that our simulation results can reproduce the observed luminosity distribution well.
