论文标题
FRB的光曲线可变性告诉我们什么有关排放机制的信息？
What does FRB light-curve variability tell us about the emission mechanism?
论文作者
论文摘要
与脉冲持续时间相比，一些快速的无线电爆发'（FRB）灯库在极短（$ t _ {\ rm rm r} \ sim10μ$ s）时表现出很大的固有调制，与脉冲持续时间（$ t _ {\ rm frb frb} \ sim1 $ ms相比，光曲线可变性时间尺度，磁通时间与脉冲持续时间的上升时间的小比例以及数据中的光谱时间相关性限制了源的紧凑性以及负责强大无线电发射的机制。当从紧凑型对象中产生辐射（$ \ gtrsim 10^{10} $ cm）时，约束最强。我们描述了可以说明观察到的$ t _ {\ rm rm}/t _ {\ rm frb} \ ll 1 $的不同物理设置，尽管有较大的排放半径。结果是无线电生产效率的显着降低，或者是在观察到的数据中可以搜索的不同光曲线特征。对于相同类别的模型，我们还表明，由于高纬度排放，如果在$ t_1 $下观察到flux $ f_1（ν_1）$，则在较低的频率$ν_2<ν_1$下，通量应至少为$（ν_2/ν_2/ν_1）^2f_1^2f_1在稍后的时间（$ t_1 $ t_1/temriation）在共同框架中的排放。一旦考虑到闪烁引起的光曲线调制，就可以测试这些功能。我们为后者提供了有关物理屏幕和闪烁状态的一系列可能性的时间尺度和连贯的带宽。最后，如果未来高度分辨的FRB光曲面被证明具有内在可变性，将延伸到$ \ simμ$ S时标，这将提供有力的证据，以支持磁层模型。
A few fast radio bursts' (FRBs) light-curves have exhibited large intrinsic modulations of their flux on extremely short ($t_{\rm r}\sim 10μ$s) time scales, compared to pulse durations ($t_{\rm FRB}\sim1$ms). Light-curve variability timescales, the small ratio of rise time of the flux to pulse duration, and the spectro-temporal correlations in the data constrain the compactness of the source and the mechanism responsible for the powerful radio emission. The constraints are strongest when radiation is produced far ($\gtrsim 10^{10}$cm) from the compact object. We describe different physical set-ups that can account for the observed $t_{\rm r}/t_{\rm FRB}\ll 1$ despite having large emission radii. The result is either a significant reduction in the radio production efficiency or distinct light-curves features that could be searched for in observed data. For the same class of models, we also show that due to high-latitude emission, if a flux $f_1(ν_1)$ is observed at $t_1$ then at a lower frequency $ν_2<ν_1$ the flux should be at least $(ν_2/ν_1)^2f_1$ at a slightly later time ($t_2=t_1ν_1/ν_2$) independent of the duration and spectrum of the emission in the comoving frame. These features can be tested, once light-curve modulations due to scintillation are accounted for. We provide the timescales and coherence bandwidths of the latter for a range of possibilities regarding the physical screens and the scintillation regime. Finally, if future highly resolved FRB light-curves are shown to have intrinsic variability extending down to $\sim μ$s timescales, this will provide strong evidence in favor of magnetospheric models.
