论文标题
钟声重复快速无线电爆发的含义
Implications of CHIME repeating fast radio bursts
论文作者
论文摘要
Chime现在检测到18个重复快速无线电爆发（FRB）。我们通过将现实的FRB种群模型拟合到数据来探讨有关中继器的能量分布和活动水平的知识。对于重复爆发的幂律能量分布dn/de〜e〜e^{ - γ}，有一个关键的指数γ_C控制中继器的分散度度量（DM，代理源距离）是底部还是最高的分布。我们发现γ_C= 7/4用于欧几里得空间中中继器的泊松等待时间分布，并进一步证明了它如何受到重复和宇宙学效应的时间聚类的影响。特别有趣的是，两个钟声中继器（FRB 181017和190417）具有较大的DM〜1000 pc/cm^3。如果：（i）能量分布为浅γ= 1.7^{+0.3} _ { - 0.1}（68％置信度）或（ii）一小部分源极具活性，则可以理解这些。在第二种情况下，这两个高DM源应比FRB 121102重复100倍以上，并且能量指数被限制为γ= 1.9^{+0.3} _ { - 0.2}（68％置信度）。无论哪种情况，此γis都与非重复的ASKAP样品的能量依赖性一致，这表明它们是从同一人群中得出的。最后，我们的模型预测了核重复分数应如何随着红移而减小，这可以与观察结果进行比较，以推断整个人群中活动水平的分布。
CHIME has now detected 18 repeating fast radio bursts (FRBs). We explore what can be learned about the energy distribution and activity level of the repeaters by fitting realistic FRB population models to the data. For a power-law energy distribution dN/dE ~ E^{-γ} for the repeating bursts, there is a critical index γ_c that controls whether the dispersion measure (DM, a proxy for source distance) distribution of repeaters is bottom or top-heavy. We find γ_c = 7/4 for Poisson wait-time distribution of repeaters in Euclidean space and further demonstrate how it is affected by temporal clustering of repetitions and cosmological effects. It is especially interesting that two of the CHIME repeaters (FRB 181017 and 190417) have large DM ~ 1000 pc/cm^3. These can be understood if: (i) the energy distribution is shallow γ= 1.7^{+0.3}_{-0.1} (68% confidence) or (ii) a small fraction of sources are extremely active. In the second scenario, these two high-DM sources should be repeating more than 100 times more frequently than FRB 121102, and the energy index is constrained to be γ= 1.9^{+0.3}_{-0.2} (68% confidence). In either case, this γis consistent with the energy dependence of the non-repeating ASKAP sample, which suggests that they are drawn from the same population. Finally, our model predicts how the CHIME repeating fraction should decrease with redshift, and this can be compared with observations to infer the distribution of activity level in the whole population.
