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arXiv 2103.16209astro-ph.HE
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用Swift资料统计搜索长伽马射线暴喷流的角非定常性

Statistical search for angular non-stationarities of long gamma-ray burst jets using Swift data

Andor Budai, Peter Raffai, Balint Borgulya, Brian Albert Dawes, Gabor Szeifert

摘要:

在Budai等人(2020)的研究中,我们认为伽马射线暴(GRB)喷流的角度非平稳性可以导致从喷流破裂时间推导出的角度值与瞬发光变曲线的可变性之间的统计联系。如果喷流的光度密度遵循幂律或均匀分布,则这种联系应该是反相关的,如果它们具有高斯分布,则应该是相关的。在这篇后续论文中,我们通过测量雨燕卫星观测到的19个长伽玛暴样本中的斯皮尔曼秩相关系数来寻找这种联系。利用16个具有明确角度测量的伽玛暴,我们发现了$ρ= -0.20_{-0.09}^{+0.09}$和$p = 0.46_{-0.19}^{+0.23}$。在样本中再增加三个伽玛暴,每个伽玛暴都有一对可能的角度值,可以加强与$ρ=-0.31_{-0.08}^{+0.07}$和$p=0.19_{-0.09}^{+0.14}$的反相关性。我们发现,这些结果是不兼容的非平稳射流具有高斯分布,并与观测到的余辉$\gtrsim\!100$伽玛暴将需要确认潜在的存在的角度变率反相关与$3σ$的意义。如果这种联系是真实的,那么伽玛暴喷流角将可以从瞬发伽玛光变曲线中得到,而不需要余辉观测。

英文摘要:

In Budai et al. (2020) we argued that angular non-stationarities of gamma-ray burst (GRB) jets can result in a statistical connection between the angle values deduced from jet break times and the variabilities of prompt light curves. The connection should be an anti-correlation if luminosity densities of jets follow a power-law or a uniform profile, and a correlation if they have a Gaussian profile. In this follow-up paper, we search for the connection by measuring Spearman's rank correlation coefficient in a sample of 19 long GRBs observed by the Swift satellite. Using 16 of the GRBs with well-defined angle measurements, we find $ρ= -0.20_{-0.09}^{+0.09}$ and $p = 0.46_{-0.19}^{+0.23}$. Adding three more GRBs to the sample, each with a pair of equally possible angle values, can strengthen the anti-correlation to $ρ=-0.31_{-0.08}^{+0.07}$ and $p=0.19_{-0.09}^{+0.14}$. We show that these results are incompatible with non-stationary jets having Gaussian profiles, and that $\gtrsim\!100$ GRBs with observed afterglows would be needed to confirm the potential existence of the angle-variability anti-correlation with $3σ$ significance. If the connection is real, GRB jet angles would be constrainable from prompt gamma light curves, without the need of afterglow observations.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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